Compound, composition, organic electroluminescent element and electronic device

ABSTRACT

A compound is represented by a formula (2) below. In the formula (2), at least one pair of a pair of X 1  and X 2 , a pair of X 2  and X 3 , a pair of X 3  and X 4 , a pair of X 4  and X 5 , a pair of X 7  and X 8 , a pair of X 8  and X 9 , a pair of X 10  and X 11 , a pair of X 11  and X 12 , a pair of X 12  and X 13 , and a pair of X 16  and X 1  are carbon atoms to be bonded to a structure represented by as formula (2a) or (2b) below,

TECHNICAL FIELD

The present invention relates to a compound, a composition, an organicelectroluminescence device and an electronic device.

BACKGROUND ART

When a voltage is applied to an organic electroluminescence device(hereinafter, occasionally referred to as an “organic EL device”), holesare injected from an anode into an emitting layer and electrons areinjected from a cathode into the emitting layer. The injected electronsand holes are recombined in the emitting layer to form excitons.According to the electron spin statistics theory, singlet excitons aregenerated at a ratio of 25% while triplet excitons are generated at aratio of 75%.

A fluorescent organic EL device uses emission caused by singlet excitonsand has been applied to a full-color display of a mobile phone, TV andthe like. An internal quantum efficiency of the fluorescent organic ELdevice is believed to be 25% at the maximum. A fluorescent organic ELdevice is required to use triplet excitons in addition to singletexcitons to promote a further efficient emission from the organic ELdevice.

In view of the above, a highly efficient fluorescent organic EL deviceusing delayed fluorescence has been proposed and studied.

For instance, a thermally activated delayed fluorescence (TADF)mechanism has been studied. The TADF mechanism uses such a phenomenonthat inverse intersystem crossing from triplet excitons to singletexcitons thermally occurs when a material having a small energydifference (AST) between singlet energy level and triplet energy levelis used. As for thermally activated delayed fluorescence, refer to, forinstance, ADACHI, Chihaya, ed. “Yuki Hando-tai no Debaisu Bussei (DevicePhysics of Organic Semiconductors)”, Kodansha Ltd., published on Apr. 1,2012, pp. 261-262. An organic EL device using the TADF mechanism isdisclosed in, for instance, non-Patent Literature 1.

An organic EL device disclosed in non-Patent Literature 1 includes anemitting layer containing a TADF compound as an assist dopant, aperylene derivative (TBPe; 2,5,8,11-tetra-tert-butylperylene) as aluminescent material, and DPEPO(bis-(2-(diphenylphosphino)phenyl)etheroxide) as a host material. This emitting layer exhibits a blue emission.

Also in a typical fluorescent organic EL device, a luminescent materialused for a blue emitting device has been studied. Patent Literatures 1to 4 disclose an acenaphtho[1,2-k]benzo[e]acephenanthrene derivative asan organic compound used for a blue emitting device.

Moreover, Patent Literature 5 shows study of a luminescent material usedfor a green emitting device in a typical fluorescent organic EL device.Patent Literature 5 discloses anacenaphtho[1,2-k]benzo[e]acephenanthrene derivative as an organiccompound used for a green emitting device.

The organic compounds of Patent Literatures 1, 2, 3, 4 and 5 each havebeen used as a luminescent material in a typical fluorescent organic ELdevice. The organic EL devices of Patent Literatures 1, 2, 3, 4 and 5 donot use the TADF mechanism.

CITATION LIST

Patent Literature(S)

-   Patent Literature 1: JP 2012-246258 A-   Patent Literature 2: JP 2010-270103 A-   Patent Literature 3: JP 2010-254610 A-   Patent Literature 4: JP 2011-231086 A-   Patent Literature 5: JP 2011-207829 A

Non-Patent Literature

-   Non-Patent Literature 1: Hajime Nakanotani et al, “High-efficiency    organic light-emitting diodes with fluorescent emitters”, NATURE    COMMUNICATIONS, 5, 4016, 2014

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

An organic electroluminescence device described in a non PatentLiterature 1 contains a TADF compound as a host material and a perylenederivative (compound TBPe) as a luminescent material, thereby exhibitinga blue emission, however, at an insufficient luminous efficiency.

Also in Patent Literatures 1 to 5, a luminous efficiency of the lightemission device containing an acenaphtho[1,2-k]benzo[e]acephenanthrenederivative is insufficient.

For this reason, an organic electroluminescence device emittable at ahigh efficiency has been desired.

An object of the invention is to provide a compound and a compositioncapable of improving a luminous efficiency of an organic EL device, toprovide an organic electroluminescence device containing the compound,and to provide an electronic device including the organicelectroluminescence device.

Means for Solving the Problems

An aspect of the invention provides a compound represented by a formula(2) below.

In the formula (2), X₁ to X₅, X₇ to X₁₃, and X₁₆ each independentlyrepresent CR_(x) or a carbon atom to be bonded to a structurerepresented by a formula (2a) or (2b) below.

X₆, X₁₄, and X₁₅ each independently represent CR_(x).

R_(x) each independently represents a hydrogen atom or a substituent.

R_(x) as the substituent is each independently selected from the groupconsisting of a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted alkylthio group having 1 to30 carbon atoms, a substituted or unsubstituted amino group, asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, a substituted or unsubstituted alkenyl group having 2 tocarbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

A plurality of R_(x) are mutually the same or different.

When a plurality of ones of X₁ to X₁₆ are CR_(x) and R_(x) is asubstituent, a plurality of R_(x) as the substituents are bonded to eachother to form a ring or are not bonded.

At least one pair of a pair of X₁ and X₂, a pair of X₂ and X₃, a pair ofX₃ and X₄, a pair of X₄ and X₅, a pair of X₇ and X₈, a pair of X₈ andX₉, a pair of X₁₀ and X₁₁, a pair of X₁₁ and X₁₂, a pair of X₁₂ and X₁₃,and a pair of X₁₆ and X₁ are carbon atoms to be bonded to the structurerepresented by the formula (2a) or (2b) below.

In the formula (2a): *2 represent bonding positions to carbon atoms atone pair of the pair of X₁ and X₂, the pair of X₃ and X₄, the pair of X₄and X₅, the pair of X₇ and X₈, the pair of X₈ and X₉, the pair of X₁₀and X₁₁, the pair of X₁₁ and X₁₂, the pair of X₁₂ and X₁₃, and the pairof X₁ and X₁ in the formula (2).

R₁₁₁ to R₁₁₄ each independently represent a hydrogen atom or asubstituent.

R₁₁₁ to R₁₁₄ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

At least one pair of a pair of R₁₁₁ and R₁₁₂, a pair of R₁₁₂ and R₁₁₃,and a pair of R₁₁₃ and R₁₁₄ are substituents, and the substituents arebonded to each other to form a ring.

In the formula (2b): *2 represent bonding positions to carbon atoms atone pair of the pair of X₁ and X₂, the pair of X₂ and X₃, the pair of X₃and X₄, the pair of X₄ and X₅, the pair of X₇ and X₈, the pair of X₈ andX₉, the pair of X₁ and X₁₁, the pair of X₁₁ and X₁₂, the pair of X₁₂ andX₁₃, and the pair of X₁₆ and X₁ in the formula (2).

R₁₁₅ and R₁₁₆ each independently represent a hydrogen atom or asubstituent.

R₁₁₅ and R₁₁₆ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

R₁₁₅ and R₁₁₆ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

X is selected from the group consisting of an oxygen atom, a sulfuratom, CR₁₁₇R₁₁₈, SiR₁₁₉R₁₂₀ and NR₁₂₁.

R₁₁₇ to R₁₂₁ each independently represent a hydrogen atom or asubstituent.

R₁₁₇ to R₁₂₁ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

R₁₁₇ and R₁₁₈ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

R₁₁₉ and R₁₂₀ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

Another aspect of the invention provides a composition containing aplurality of compounds each represented by a formula (2) below.

In the formula (2), X₁ to X₅, X₇ to X₁₃, and X₁₆ each independentlyrepresent CR_(x) or a carbon atom to be bonded to a structurerepresented by a formula (2a) or (2b) below.

X₆, X₁₄, and X₁₅ each independently represent CR_(x).

R_(x) each independently represents a hydrogen atom or a substituent.

R_(x) as the substituent is each independently selected from the groupconsisting of a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted alkylthio group having 1 to30 carbon atoms, a substituted or unsubstituted amino group, asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, a substituted or unsubstituted alkenyl group having 2 tocarbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

A plurality of R_(x) are mutually the same or different.

When a plurality of ones of X₁ to X₁₆ are CR_(x) and R_(x) is asubstituent, a plurality of R_(x) as the substituents are bonded to eachother to form a ring or are not bonded.

At least one pair of a pair of X₁ and X₂, a pair of X₂ and X₃, a pair ofX₃ and X₄, a pair of X₄ and X₅, a pair of X₇ and X₈, a pair of X₈ andX₉, a pair of X₁ and X₁₁, a pair of X₁₁ and X₁₂, a pair of X₁₂ and X₁₃,and a pair of X₄ and X₅ are carbon atoms to be bonded to the structurerepresented by the formula (2a) or (2b) below.

In the formula (2a): *2 represent bonding positions to carbon atoms atone pair of the pair of X₁ and X₂, the pair of X₃ and X₄, the pair of X₄and X₅, the pair of X₇ and X₈, the pair of X₈ and X₉, the pair of X₁₀and X₁₁, the pair of X₁₁ and X₁₂, the pair of X₁₂ and X₁₃, and the pairof X₁₆ and X₁ in the formula (2).

R₁₁₁ to R₁₁₄ each independently represent a hydrogen atom or asubstituent.

R₁₁₁ to R₁₁₄ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

At least one pair of a pair of R₁₁₁ and R₁₁₂, a pair of R₁₁₂ and R₁₁₃,and a pair of R₁₁₃ and R₁₁₄ are substituents, and the substituents arebonded to each other to form a ring.

In the formula (2b): *2 represent bonding positions to carbon atoms atone pair of the pair of X₁ and X₂, the pair of X₂ and X₃, the pair of X₃and X₄, the pair of X₄ and X₅, the pair of X₇ and X₈, the pair of X₈ andX₉, the pair of X₁₀ and X₁₁, the pair of X₁₁ and X₁₂, the pair of X₁₂and X₁₃, and the pair of X₁₆ and X₁ in the formula (2).

R₁₁ and R₁₁₆ each independently represent a hydrogen atom or asubstituent.

R₁₁₅ and R₁₁₆ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

R₁₁₅ and R₁₁₆ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

X is selected from the group consisting of an oxygen atom, a sulfuratom, CR₁₁₇R₁₁, SiR₁₁₉R₁₂₀ and NR₁₂₁.

R₁₁₇ to R₁₂₁ each independently represent a hydrogen atom or asubstituent.

R₁₁₇ to R₁₂₁ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

R₁₁₇ and R₁₁₈ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

R₁₁₉ and R₁₂₀ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

Still another aspect of the invention provides an organicelectroluminescence device including: an anode; an emitting layer; and acathode, in which the emitting layer contains a first compound and asecond compound, the second compound being the compound according to theabove aspect of the invention.

A further aspect of the invention provides an electronic deviceincluding the organic electroluminescence device according to the aboveaspect of the invention.

The above aspects of the invention enable to provide a compound and acomposition capable of improving a luminous efficiency of an organic ELdevice, to provide an organic electroluminescence device containing thecompound, and to provide an electronic device including the organicelectroluminescence device.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 schematically shows an exemplary arrangement of an organic ELdevice according to a first exemplary embodiment of the invention.

FIG. 2 is a schematic illustration of a measuring device of transientPL.

FIG. 3 shows an example of a decay curve of the transient PL.

FIG. 4 shows a relationship between energy levels of a first compoundand a second compound and an energy transfer between the first compoundand the second compound in an emitting layer of an exemplary organicelectroluminescence device of the first exemplary embodiment of theinvention.

FIG. 5 shows a relationship between energy levels of a first compound, asecond compound and a third compound and an energy transfer between thefirst compound, the second compound and the third compound in anemitting layer of an exemplary organic electroluminescence device of asecond exemplary embodiment of the invention.

DESCRIPTION OF EMBODIMENT(S) First Exemplary Embodiment

Compound

A compound of a first exemplary embodiment is represented by a formula(2) below.

In the formula (2): X₁ to X₅, X₇ to X₁₃, and X₁₆ each independentlyrepresent CR_(x) or a carbon atom to be bonded to a structurerepresented by a formula (2a) or (2b) below.

X₆, X₁₄, and X₁₅ each independently represent CR_(x).

R_(x) each independently represents a hydrogen atom or a substituent.

R_(x) as the substituent is each independently selected from the groupconsisting of a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted alkylthio group having 1 to30 carbon atoms, a substituted or unsubstituted amino group, asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, a substituted or unsubstituted alkenyl group having 2 tocarbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

A plurality of R_(x) are mutually the same or different.

When a plurality of ones of X₁ to X₁₆ are CR_(x) and R_(x) is asubstituent, a plurality of R_(x) as the substituents are bonded to eachother to form a ring or are not bonded.

At least one pair of a pair of X₁ and X₂, a pair of X₂ and X₃, a pair ofX₃ and X₄, a pair of X₄ and X₅, a pair of X₇ and X₈, a pair of X₈ andX₉, a pair of X₁₀ and X₁₁, a pair of X₁₁ and X₁₂, a pair of X₁₂ and X₁₃,and a pair of X₁₆ and X₁ are carbon atoms to be bonded to the structurerepresented by the formula (2a) or (2b) below.

In the formula (2a), *2 represent bonding positions to carbon atoms atone pair of the pair of X₁ and X₂, the pair of X₃ and X₄, the pair of X₄and X₅, the pair of X₇ and X₈, the pair of X₈ and X₉, the pair of X₁₀and X₁₁, the pair of X₁₁ and X₁₂, the pair of X₁₂ and X₁₃, and the pairof X₁ and X₁ in the formula (2).

R₁₁₁ to R₁₁₄ each independently represent a hydrogen atom or asubstituent.

R₁₁₁ to R₁₁₄ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

At least one pair of a pair of R₁₁₁ and R₁₁₂, a pair of R₁₁₂ and R₁₁₃,and a pair of R₁₁₃ and R₁₁₄ are substituents. The substituents arebonded to each other to form a ring.

In the formula (2b), *2 represent bonding positions to carbon atoms atone pair of the pair of X₁ and X₂, the pair of X₂ and X₃, the pair of X₃and X₄, the pair of X₄ and X₅, the pair of X₇ and X₈, the pair of X₈ andX₉, the pair of X₁₀ and X₁₁, the pair of X₁₁ and X₁₂, the pair of X₁₂and X₁₃, and the pair of X₁₆ and X₁ in the formula (2).

R₁₁₅ and R₁₁₆ each independently represent a hydrogen atom or asubstituent.

R₁₁₅ and R₁₁₆ as the substituent are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

R₁₁₅ and R₁₁₆ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

X is selected from the group consisting of an oxygen atom, a sulfuratom, CR₁₁₇R₁₁₈, SiR₁₁₉R₁₂₀ and NR₁₂₁.

R₁₁₇ to R₁₂₁ each independently represent a hydrogen atom or asubstituent.

R₁₁₇ to R₁₂₁ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

R₁₁₇ and R₁₁₈ as the substituents are bonded to each other to form aring, or are not bonded to each other.

R₁₁₉ and R₁₂₀ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

In the exemplary embodiment, R_(x) in the formula (2) is eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, R₁₁₁ to R₁₁₄ in the formula (2a) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, R₁₁₅ to R₁₂₁ in the formula (2b) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the formula (2) representing the compound of the exemplaryembodiment, at least one pair of the pair of X₁ and X₂ and the pair ofX₃ and X₄ are preferably carbon atoms to be bonded to the structurerepresented by the formula (2a).

In the compound of the exemplary embodiment, the structure representedby the formula (2a) is preferably a structure represented by a formula(2a-1) below.

In the formula (2a-1), *2 represents the same as *2 of the formula (2a).

R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ each independently represent a hydrogen atomor a substituent.

R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ as the substituents are each independentlyselected from the group consisting of a substituted or unsubstitutedalkyl group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkylthio group having 1 to 30 carbon atoms, a substituted orunsubstituted amino group, a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, a substituted orunsubstituted alkenyl group having 2 to 30 carbon atoms, a substitutedor unsubstituted aryloxy group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted arylthio group having 6 to 30 ring carbonatoms, a substituted or unsubstituted phosphanyl group, a substituted orunsubstituted phosphoryl group, a substituted or unsubstituted silylgroup, a substituted or unsubstituted arylcarbonyl group having 6 to 30ring carbon atoms, a cyano group, a nitro group, a carboxy group, and ahalogen atom.

Adjacent ones of R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ as the substituents arebonded to each other to further form a ring, or are not bonded to eachother.

In the exemplary embodiment, R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ in the formula(2a-1) are each independently preferably a hydrogen atom, or a groupselected from the group consisting of an aryl group having 6 to 30 ringcarbon atoms, a heteroaryl group having 5 to 30 ring atoms, an alkylgroup having 1 to 30 carbon atoms (a linear or branched alkyl group), ahalogen atom, and a cyano group.

In the exemplary embodiment, the compound represented by the formula (2)is preferably represented by a formula (21A) below.

In the formula (21A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) in the formula (2), and R₁₁₁, R₁₁₂ and R₁₂₂to R₁₂₅ respectively represent the same as R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅in the formula (2a-1).

In the exemplary embodiment, when adjacent ones of the substituents ofR₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ in the formula (21A) are bonded to eachother to further form a ring, a pair of R₁₁₁ and R₁₁₂ or a pair of R₁₂₂and R₁₂₃ are preferably bonded to each other to further form a ring.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (21B) below.

In the formula (21B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) in the formula (2), and R₁₁₁,R₁₁₂ and R₁₂₂ to R₁₂₅ respectively represent the same as R₁₁₁, R₁₁₂ andR₁₂₂ to R₁₂₅ in the formula (2a-1).

In the exemplary embodiment, when adjacent ones of the substituents ofR₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ in the formula (21B) are bonded to eachother to further form a ring, a pair of R₁₁₁ and R₁₁₂ or a pair of R₁₂₂and R₁₂₃ are preferably bonded to each other to further form a ring.

In the compound of the exemplary embodiment, the structure representedby the formula (2a) is also preferably a structure represented by aformula (2a-2) below.

In the formula (2a-2), *2 represents the same as *2 of the formula (2a).

R₁₁₃, R₁₁₄ and R₁₂₂ to R₁₂₅ each independently represent a hydrogen atomor a substituent.

R₁₁₃, R₁₁₄ and R₁₂₂ to R₁₂₅ as the substituents are each independentlyselected from the group consisting of a substituted or unsubstitutedalkyl group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkylthio group having 1 to 30 carbon atoms, a substituted orunsubstituted amino group, a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, a substituted orunsubstituted alkenyl group having 2 to 30 carbon atoms, a substitutedor unsubstituted aryloxy group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted arylthio group having 6 to 30 ring carbonatoms, a substituted or unsubstituted phosphanyl group, a substituted orunsubstituted phosphoryl group, a substituted or unsubstituted silylgroup, a substituted or unsubstituted arylcarbonyl group having 6 to 30ring carbon atoms, a cyano group, a nitro group, a carboxy group, and ahalogen atom.

Adjacent ones of R₁₁₃, R₁₁₄ and R₁₂₂ to R₁₂₅ as the substituents arebonded to each other to further form a ring, or are not bonded to eachother.

In the exemplary embodiment, R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ in the formula(2a-2) are each independently preferably a hydrogen atom, or a groupselected from the group consisting of an aryl group having 6 to 30 ringcarbon atoms, a heteroaryl group having 5 to 30 ring atoms, an alkylgroup having 1 to 30 carbon atoms (a linear or branched alkyl group), ahalogen atom, and a cyano group.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (22A) below.

In the formula (22A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) in the formula (2), and R₁₁₃, R₁₁₄ and R₁₂₂to R₁₂₅ respectively represent the same as R₁₁₃, R₁₁₄ and R₁₂₂ to R₁₂₅in the formula (2a-2).

In the exemplary embodiment, when adjacent ones of the substituents ofR₁₁₃, R₁₁₄ and R₁₂₂ to R₁₂₅ in the formula (22A) are bonded to eachother to further form a ring, a pair of R₁₁₃ and R₁₁₄ or a pair of R₁₂₂and R₁₂₃ are preferably bonded to each other to further form a ring.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (22B) below.

In the formula (22B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) in the formula (2), and R₁₁₃,R₁₁₄ and R₁₂₂ to R₁₂₅ respectively represent the same as R₁₁₃, R₁₁₄ andR₁₂₂ to R₁₂₅ in the formula (2a-2).

In the exemplary embodiment, when adjacent ones of the substituents ofR₁₁₃, R₁₁₄ and R₁₂₂ to R₁₂₅ in the formula (22B) are bonded to eachother to further form a ring, a pair of R₁₁₃ and R₁₁₄ or a pair of R₁₂₂and R₁₂₃ are preferably bonded to each other to further form a ring.

In the exemplary embodiment, at least one pair of the pair of X₁ and X₂,the pair of X₂ and X₃ and the pair of X₃ and X₄ in the formula (2) arealso preferably carbon atoms to be bonded to the structure representedby the formula (2b).

In the exemplary embodiment, the compound in which at least one pair ofthe pair of X₁ and X₂, the pair of X₂ and X₃ and the pair of X₃ and X₄in the formula (2) are carbon atoms to be bonded to the structurerepresented by the formula (2b) is exemplified by a compound representedby a formula (23A), a compound represented by a formula (23B), acompound represented by a formula (24A), and a compound represented by aformula (24B).

In the formula (23A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2).

In the formula (23B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) of the formula (2).

In the formula (24A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2).

In the formula (24B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) of the formula (2).

In the formulae (23A), (23B), (24A) and (24B), R₁₁₅, R₁₁₆ and Xrespectively represent the same as R₁₁₅, R₁₁₆ and X of the formula (2b).

In the formulae (23A), (23B), (24A) and (24B), preferably, both of R₁₁₅and R₁₁₆ are substituents and R₁₁₅ and R₁₁₆ as the substituents arebonded to each other to further form a ring.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (25A) below.

In the formula (25A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2), and X represents thesame as X of the formula (2b).

R₁₂₆ to R₁₂₉ each independently represent a hydrogen atom or asubstituent.

R₁₂₆ to R₁₂₉ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

Adjacent ones of R₁₂₆ to R₁₂₉ as the substituents are bonded to eachother to further form a ring, or are not bonded to each other.

In the exemplary embodiment, R₁₂₆ to R₁₂₉ in the formula (25A) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (25B) below.

In the formula (25B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) of the formula (2), and Xrepresents the same as X of the formula (2b).

R₁₂₆ to R₁₂₉ each independently represent a hydrogen atom or asubstituent.

R₁₂₆ to R₁₂₉ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

Adjacent ones of R₁₂₆ to R₁₂₉ as the substituents are bonded to eachother to further form a ring, or are not bonded to each other.

In the exemplary embodiment, R₁₂₆ to R₁₂₉ in the formula (25B) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (26A) below.

In the formula (26A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2), and X represents thesame as X of the formula (2b).

R₁₂₆ to R₁₂₉ each independently represent a hydrogen atom or asubstituent.

R₁₂₆ to R₁₂₉ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

Adjacent ones of R₁₂₆ to R₁₂₉ as the substituents are bonded to eachother to further form a ring, or are not bonded to each other.

In the exemplary embodiment, R₁₂₆ to R₁₂₉ in the formula (26A) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (26B) below.

In the formula (26B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) of the formula (2), and Xrepresents the same as X of the formula (2b).

R₁₂₆ to R₁₂₉ each independently represent a hydrogen atom or asubstituent.

R₁₂₆ to R₁₂₉ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

Adjacent ones of R₁₂₆ to R₁₂₉ as the substituents are bonded to eachother to further form a ring, or are not bonded to each other.

In the exemplary embodiment, R₁₂₆ to R₁₂₉ in the formula (26B) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (27A) below.

In the formula (27A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2), and X represents thesame as X of the formula (2b).

R₁₃₀ and R₁₃₁ each independently represent a hydrogen atom or asubstituent.

R₁₃₀ and R₁₃₁ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

X₂₀ is selected from the group consisting of an oxygen atom, a sulfuratom, CR₁₃₂R₁₃₃, SiR₁₃₄R₁₃₅ and NR₁₃₆.

R₁₃₂ to R₁₃₆ each independently represent a hydrogen atom or asubstituent.

R₁₃₂ to R₁₃₆ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

Adjacent ones of R₁₃₀ to R₁₃₆ as the substituents are bonded to eachother to further form a ring, or are not bonded to each other.

In the exemplary embodiment, R₁₃₀ to R₁₃₆ in the formula (27A) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (27B) below.

In the formula (27B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) of the formula (2), and Xrepresents the same as X of the formula (2b).

R₁₃₀ and R₁₃₁ each independently represent a hydrogen atom or asubstituent.

R₁₃₀ and R₁₃₁ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

X₂₀ is selected from the group consisting of an oxygen atom, a sulfuratom, CR₁₃₂R₁₃₃, SiR₁₃₄R₁₃₅ and NR₁₃₆.

R₁₃₂ to R₁₃₆ each independently represent a hydrogen atom or asubstituent.

R₁₃₂ to R₁₃₆ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

Adjacent ones of R₁₃₀ to R₁₃₆ as the substituents are bonded to eachother to further form a ring, or are not bonded to each other.

In the exemplary embodiment, R₁₃₀ to R₁₃₆ in the formula (27B) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (28A) below.

In the formula (28A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2), and X represents thesame as X of the formula (2b).

R₁₃₀ and R₁₃₁ each independently represent a hydrogen atom or asubstituent.

R₁₃₀ to R₁₃₁ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

X₂₀ is selected from the group consisting of an oxygen atom, a sulfuratom, CR₁₃₂R₁₃₃, SiR₁₃₄R₁₃₅ and NR₁₃₆.

R₁₃₂ to R₁₃₆ each independently represent a hydrogen atom or asubstituent.

R₁₃₂ to R₁₃₆ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

Adjacent ones of R₁₃₀ to R₁₃₆ as the substituents are bonded to eachother to further form a ring, or are not bonded to each other.

In the exemplary embodiment, R₁₃₀ to R₁₃₆ in the formula (28A) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, the compound represented by the formula (2)is also preferably represented by a formula (28B) below.

In the formula (28B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) of the formula (2), and Xrepresents the same as X of the formula (2b).

R₁₃₀ and R₁₃₁ each independently represent a hydrogen atom or asubstituent.

R₁₃₀ and R₁₃₁ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

X₂₀ is selected from the group consisting of an oxygen atom, a sulfuratom, CR₁₃₂R₁₃₃, SiR₁₃₄R₁₃₅ and NR₁₃₆.

R₁₃₂ to R₁₃₆ each independently represent a hydrogen atom or asubstituent.

R₁₃₂ to R₁₃₆ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

Adjacent ones of R₁₃₀ to R₁₃₆ as the substituents are bonded to eachother to further form a ring, or are not bonded to each other.

In the exemplary embodiment, R₁₃₀ to R₁₃₆ in the formula (28B) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the formula (2) representing the compound of the exemplaryembodiment, X₆ is preferably CR₆, X₁₅ is preferably CR₁₅, and R₆ and R₁₅are each independently preferably a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms, more preferably a substituted orunsubstituted phenyl group.

In the formula (2) representing the compound of the exemplaryembodiment, preferably, X₅ is CR₅, X₆ is CR₆, X₇ is CR₇, X₈ is CR₈, X₉is CR₉, X₁₀ is CR₁₀, X₁₁ is CR₁₁, X₁₂ is CR₁₂, X₁₃ is CR₁₃, X₁₄ is CR₁₄,X₁₅ is CR₁₅, X₁₆ is CR₁₆, R₆ and R₁₅ are each independently asubstituted or unsubstituted phenyl group, and R₅, R₇ to R₁₄, and R₁₆are hydrogen atoms.

The compound of the exemplary embodiment can improve a luminousefficiency of an organic EL device.

This is considered to be attributed to the above-described particularstructure of the compound of the exemplary embodiment. At least one ofthe structures represented by the formulae (2a) and (2b) is bonded tothe structure represented by the formula (2). Conjugation is thus addedto an acenaphtho[1,2-k]benzo[e]acephenanthrene skeleton, therebyallowing an increase in a molar absorbance coefficient and a decrease inStokes shift. Accordingly, it is considered that, by using the compoundof the exemplary embodiment as the luminescent material (a dopant) ofthe organic EL device, the compound can sufficiently absorb transferenergy from a host to the dopant, thereby improving the luminousefficiency.

In order to improve the luminous efficiency of the organic EL device ina blue wavelength region, conjugate addition to theacenaphtho[1,2-k]benzo[e]acephenanthrene skeleton is preferablyperformed by increasing the number of the fused ring by addition of astructure such as the structure represented by the formula (2a-1) or byincreasing the number of the fused ring so as to form the structurerepresented by the formula (25A), (25B), (26A) or (26B). Morepreferably, conjugate addition is performed by increasing the number ofthe fused ring so as to form the structure represented by the formula(21A), (21B), (25A) or (25B). Conjugate addition by such an increase inthe number of the fused ring avoids an excessively small singlet energyand a shift of an emission peak toward a long wavelength. Accordingly,it is expected that the luminous efficiency is improvable while theemission peak is kept in the blue emission region.

Manufacturing Method of Compound

The compound according to the exemplary embodiment can be manufacturedby, for instance, a method described in Examples described below. Thecompound of the exemplary embodiment can be manufactured by applicationof known substitution reactions and/or materials depending on a targetcompound according to reactions described later in Examples.

Examples of the compound according to the exemplary embodiment are givenbelow. It should be understood that examples of the compound accordingto the exemplary embodiment are merely illustrative and are not intendedto limit the scope of the invention.

Composition

A composition of the exemplary embodiment contains a plurality ofcompounds each represented by the formula (2) below.

in the formula (2): X₁ to X₅, X₇ to X₁₃, and X₁₆ each independentlyrepresent CR_(x) or a carbon atom to be bonded to the structurerepresented by the formula (2a) or (2b) below.

X₆, X₁₄, and X₁₅ each independently represent CRx.

R_(x) each independently represents a hydrogen atom or a substituent.

R_(x) as the substituent is each independently selected from the groupconsisting of a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted alkylthio group having 1 to30 carbon atoms, a substituted or unsubstituted amino group, asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, a substituted or unsubstituted alkenyl group having 2 tocarbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

A plurality of R_(x) are mutually the same or different.

When a plurality of ones of X₁ to X₁₆ are CR_(x) and R_(x) is asubstituent, a plurality of R_(x) as the substituents are bonded to eachother to form a ring or are not bonded.

At least one pair of the pair of X₁ and X₂, the pair of X₂ and X₃, thepair of X₃ and X₄, the pair of X₄ and X₅, the pair of X₇ and X₈, thepair of X₈ and X₉, the pair of X₁₀ and X₁₁, the pair of X₁₁ and X₁₂, thepair of X₁₂ and X₁₃, and the pair of X₁₆ and X₁ are carbon atoms to bebonded to the structure represented by the formula (2a) or (2b) below.

In the formula (2a), *2 represent bonding positions to carbon atoms atone pair of the pair of X₁ and X₂, the pair of X₃ and X₄, the pair of X₄and X₅, the pair of X₇ and X₈, the pair of X₈ and X₉, the pair of X₁₀and X₁₁, the pair of X₁₁ and X₁₂, the pair of X₁₂ and X₁₃, and the pairof X₁₆ and X₁ in the formula (2).

R₁₁₁ to R₁₁₄ each independently represent a hydrogen atom or asubstituent.

R₁₁₁ to R₁₁₄ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

At least one pair of the pair of R₁₁₁ and R₁₁₂, the pair of R₁₁₂ andR₁₁₃, and the pair of R₁₁₃ and R₁₁₄ are substituents. The substituentsare bonded to each other to form a ring.

In the formula (2b), *2 represent bonding positions to carbon atoms atone pair of the pair of X₁ and X₂, the pair of X₂ and X₃, the pair of X₃and X₄, the pair of X₄ and X₅, the pair of X₇ and X₈, the pair of X₈ andX₉, the pair of X₁ and X₁₁, the pair of X₁₁ and X₁₂, the pair of X₁₂ andX₁₃, and the pair of X₁₆ and X₁ in the formula (2).

R₁₁₅ and R₁₁₆ each independently represent a hydrogen atom or asubstituent.

R₁₁₅ and R₁₁₆ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

R₁₁₅ and R₁₁₆ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

X is selected from the group consisting of an oxygen atom, a sulfuratom, CR₁₁₇R₁₁₈, SiR₁₁₉R₁₂₀ and NR₁₂₁.

R₁₁₇ to R₁₂₁ each independently represent a hydrogen atom or asubstituent.

R₁₁₇ to R₁₂₁ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

R₁₁₇ and R₁₁₈ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

R₁₁₉ and R₁₂₀ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.

In the exemplary embodiment, R_(x) in the formula (2) is eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, R₁₁₁ to R₁₁₄ in the formula (2a) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, R₁₁₅ to R₁₂₁ in the formula (2b) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the formula (2) representing the composition of the exemplaryembodiment, at least one pair of the pair of X₁ and X₂ and the pair ofX₃ and X₄ are preferably carbon atoms to be bonded to the structurerepresented by the formula (2a).

In the composition of the exemplary embodiment, the structurerepresented by the formula (2a) is preferably the structure representedby the formula (2a-1) below.

In the formula (2a-1), *2 represents the same as *2 of the formula (2a).

R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ each independently represent a hydrogen atomor a substituent.

R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ as the substituents are each independentlyselected from the group consisting of a substituted or unsubstitutedalkyl group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkylthio group having 1 to 30 carbon atoms, a substituted orunsubstituted amino group, a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, a substituted orunsubstituted alkenyl group having 2 to 30 carbon atoms, a substitutedor unsubstituted aryloxy group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted arylthio group having 6 to 30 ring carbonatoms, a substituted or unsubstituted phosphanyl group, a substituted orunsubstituted phosphoryl group, a substituted or unsubstituted silylgroup, a substituted or unsubstituted arylcarbonyl group having 6 to 30ring carbon atoms, a cyano group, a nitro group, a carboxy group, and ahalogen atom.

Adjacent ones of R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ as the substituents arebonded to each other to further form a ring, or are not bonded to eachother.

In the exemplary embodiment, R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ in the formula(2a-1) are each independently preferably a hydrogen atom, or a groupselected from the group consisting of an aryl group having 6 to 30 ringcarbon atoms, a heteroaryl group having 5 to 30 ring atoms, an alkylgroup having 1 to 30 carbon atoms (a linear or branched alkyl group), ahalogen atom, and a cyano group.

The composition of the exemplary embodiment preferably contains thecompound represented by the formula (21A) below and the compoundrepresented by the formula (21B) below as the compounds each representedby the formula (2).

In the formula (21A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2).

In the formula (21B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) of the formula (2).

In the formulae (21A) and (21B), R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅respectively represent the same as R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ of theformula (2a-1).

In the exemplary embodiment, when adjacent ones of the substituents ofR₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ in the formula (21A) are bonded to eachother to further form a ring, a pair of R₁₁₁ and R₁₁₂ or a pair of R₁₂₂and R₁₂₃ are preferably bonded to each other to further form a ring.

In the exemplary embodiment, when adjacent ones of the substituents ofR₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ in the formula (21B) are bonded to eachother to further form a ring, a pair of R₁₁₁ and R₁₁₂ or a pair of R₁₂₂and R₁₂₃ are preferably bonded to each other to further form a ring.

In the formula (2) representing the composition of the exemplaryembodiment, at least one pair of the pair of X₁ and X₂, the pair of X₂and X₃ and the pair of X₃ and X₄ are also preferably carbon atoms to bebonded to the structure represented by the formula (2b).

The composition of the exemplary embodiment also preferably contains thecompound represented by the formula (25A) below and the compoundrepresented by the formula (25B) below as the compound represented bythe formula (2).

In the formula (25A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2).

In the formula (25B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) of the formula (2).

In the formulae (25A) and (25B), X represents the same as X of theformula (2b).

R₁₂₆ to R₁₂₉ each independently represent a hydrogen atom or asubstituent.

R₁₂₆ to R₁₂₉ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

Adjacent ones of R₁₂₆ to R₁₂₉ as the substituents are bonded to eachother to further form a ring, or are not bonded to each other.

In the exemplary embodiment, R₁₂₆ to R₁₂₉ in the formula (25A) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, R₁₂₆ to R₁₂₉ in the formula (25B) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

The composition of the exemplary embodiment also preferably contains thecompound represented by the formula (26A) below and the compoundrepresented by the formula (26B) below as the compound represented bythe formula (2).

In the formula (26A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2).

In the formula (26B), X₁, X₂, X₅ to X₁₆ and R_(x) respectively representthe same as X₁, X₂, X₅ to X₁₆ and R_(x) of the formula (2).

In the formulae (26A) and (26B), X represents the same as X of theformula (2b).

R₁₂₆ to R₁₂₉ each independently represent a hydrogen atom or asubstituent.

R₁₂₆ to R₁₂₉ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to carbon atoms, a substituted or unsubstituted aryloxy group having 6to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom.

Adjacent ones of R₁₂₆ to R₁₂₉ as the substituents are bonded to eachother to further form a ring, or are not bonded to each other.

In the exemplary embodiment, R₁₂₆ to R₁₂₉ in the formula (26A) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

In the exemplary embodiment, R₁₂₆ to R₁₂₉ in the formula (26B) are eachindependently preferably a hydrogen atom, or a group selected from thegroup consisting of an aryl group having 6 to 30 ring carbon atoms, aheteroaryl group having 5 to 30 ring atoms, an alkyl group having 1 to30 carbon atoms (a linear or branched alkyl group), a halogen atom, anda cyano group.

A specific structure and a preferable form of the compound representedby the formula (2) contained in the composition of the exemplaryembodiment are exemplified by the structures represented by the formulaeof the compound for the composition in the exemplary embodiment, and thestructures represented by the formulae and preferable forms of thecompound in the description of the compound in the above exemplaryembodiment.

Specific examples ([1] to [51]) of a combination of the compoundscontained in the composition of the exemplary embodiment are shownbelow. It should be understood that examples of the composition of theexemplary embodiment are merely illustrative and are not intended tolimit the scope of the invention.

The composition of the exemplary embodiment can improve a luminousefficiency of the organic EL device.

Moreover, the composition of the exemplary embodiment can improve theluminous efficiency of the organic EL device particularly in the bluewavelength region.

Organic EL Device

Arrangement(s) of Organic EL Device

Arrangement(s) of an organic EL device according to an exemplaryembodiment will be described below.

The organic EL device in the exemplary embodiment includes a pair ofelectrodes and an organic layer between the pair of electrodes. Theorganic layer includes at least one layer formed of an organic compound.Alternatively, the organic layer includes a plurality of layers eachformed of an organic compound. The organic layer may further include aninorganic compound. In the organic EL device in the exemplaryembodiment, at least one layer of the organic layer(s) is the emittinglayer. Specifically, for instance, the organic layer may consist of asingle emitting layer, or may include layers usable in a typical organicEL device. The layers usable in a typical organic EL device are notlimited to particular ones, but, for instance, at least one layerselected from the group consisting of a hole injecting layer, a holetransporting layer, an electron injecting layer, an electrontransporting layer and a blocking layer.

Typical device arrangements of the organic EL device include thefollowing arrangements (a) to (f) and the like:

(a) anode/emitting layer/cathode;

(b) anode/hole injecting-transporting layer/emitting layer/cathode;

(c) anode/emitting layer/electron injecting-transporting layer/cathode;

(d) anode/hole injecting-transporting layer/emitting layer/electroninjecting-transporting layer/cathode;

(e) anode/hole injecting-transporting layer/emitting layer/blockinglayer/electron injecting-transporting layer/cathode; and

(f) anode/hole injecting-transporting layer/blocking layer/emittinglayer/blocking layer/electron injecting-transporting layer/cathode.

The arrangement (d) is preferably used among the above arrangements.However, the arrangement according to the invention is not limited tothe above arrangements. The “emitting layer” refers to an organic layerhaving an emitting function. The term “hole injecting-transportinglayer” means at least one of a hole injecting layer and a holetransporting layer. The term “electron injecting-transporting layer”means at least one of an electron injecting layer and an electrontransporting layer. When the organic EL device includes the holeinjecting layer and the hole transporting layer, the hole injectinglayer is preferably provided between the hole transporting layer and theanode. When the organic EL device includes the electron injecting layerand the electron transporting layer, the electron injecting layer ispreferably provided between the electron transporting layer and thecathode. The hole injecting layer, the hole transporting layer, theelectron transporting layer and the electron injecting layer may eachconsist of a single layer or a plurality of layers.

FIG. 1 schematically shows an arrangement of an exemplary organic ELdevice according to the exemplary embodiment.

An organic EL device 1 includes a light-transmissive substrate 2, ananode 3, a cathode 4 and an organic layer 10 disposed between the anode3 and the cathode 4. The organic layer 10 includes a hole injectinglayer 6, a hole transporting layer 7, an emitting layer 5, an electrontransporting layer 8, and an electron injecting layer 9. In the organiclayer 10, the hole injecting layer 6, the hole transporting layer 7, theemitting layer 5, the electron transporting layer 8, and the electroninjecting layer 9 are laminated on the anode 3 in this sequence.

Emitting Layer

The emitting layer 5 of the organic EL device 1 contains a firstcompound and a second compound. The emitting layer 5 may include a metalcomplex. The emitting layer 5 preferably includes no phosphorescentmetal complex.

The first compound is also preferably a host material (occasionallyreferred to as a matrix material). The second compound is alsopreferably a dopant material (occasionally referred to as a guestmaterial, emitter or luminescent material).

In the exemplary embodiment, the emitting layer 5 may include aplurality of the second compounds.

In the exemplary embodiment, an arrangement in which the emitting layer5 includes a plurality of the second compounds also encompasses, forinstance, an arrangement in which the emitting layer 5 includes thecomposition of the above exemplary embodiment.

First Compound

The first compound may be a delayed fluorescent compound or a compoundexhibiting no delayed fluorescence. The first compound is preferably adelayed fluorescent compound.

The first compound in a form of a delayed fluorescent compound ispreferably a compound represented by a formula (1) below.

In the formula (1): A is a group having a partial structure selectedfrom the group consisting of partial structures represented by formulae(a-1) to (a-7) below.

A plurality of A are mutually the same or different.

The plurality of A are mutually bonded to form a saturated orunsaturated ring, or not bonded.

B is a group having a partial structure selected from the groupconsisting of partial structures represented by formulae (b-1) to (b-6)below.

A plurality of B are mutually the same or different.

The plurality of B are mutually bonded to form a saturated orunsaturated ring, or not bonded.

a, b and d are each independently an integer of 1 to 5.

c is an integer of 0 to 5.

When c is 0, A is bonded to B by a single bond or a spiro bond.

When c is an integer of 1 to 5, L is a linking group selected from thegroup consisting of a substituted or unsubstituted aryl group having 6to 30 ring carbon atoms, and a substituted or unsubstituted heteroarylgroup having 5 to 30 ring atoms, When c is an integer of 2 to 5, aplurality of L are mutually the same or different.

The plurality of L are mutually bonded to form a saturated orunsaturated ring, or not bonded.

In the formulae (b-1) to (b-6): R each independently represents ahydrogen atom or a substituent.

R as the substituent is each independently selected from the groupconsisting of a substituted or unsubstituted aryl group having 6 to 30ring carbon atoms, a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring atoms, and a substituted or unsubstituted alkylgroup having 1 to 30 carbon atoms.

A plurality of R are mutually the same or different.

The plurality of R are mutually bonded to form a saturated orunsaturated ring, or not bonded.

In the formula (1), A is an acceptor (electron accepting) moiety and Bis a donor (electron donating) moiety.

Examples of the group having the partial structure selected from thegroup consisting of the partial structures represented by the respectiveformulae (a-1) to (a-7) are shown below.

For instance, a group having the partial structure of the formula (a-3)is exemplified by a group represented by a formula (a-3-1).

In the formula (a-3-1), X_(a) is a single bond, an oxygen atom, a sulfuratom, or a carbon atom to be bonded to L or B in the formula (1).

For instance, a group having the partial structure of the formula (a-5)is exemplified by a group represented by a formula (a-5-1).

Examples of the group having the partial structure selected from thegroup consisting of the partial structures represented by the formulae(b-1) to (b-6) are shown below.

For instance, a group having the partial structure of the formula (b-2)is exemplified by a group represented by a formula (b-2-1).

In the formula (b-2-1), X_(b) is a single bond, an oxygen atom, a sulfuratom, CR_(b1)R_(b2) or a carbon atom to be bonded to L or A in theformula (1).

The group represented by the formula (b-2-1) in which X_(b) is a singlebond is a group represented by a formula (b-2-2). The group representedby the formula (b-2-1) in which X_(b) is an oxygen atom is a grouprepresented by a formula formula (b-2-3). The group represented by theformula (b-2-1) in which X_(b) is a sulfur atom is a group representedby a formula (b-2-4). The group represented by the formula (b-2-1) inwhich X_(b) is CR_(b1)R_(b2) is a group represented by a formula(b-2-5).

R_(b1) and R_(b2) are each independently a hydrogen atom or asubstituent. R_(b1) and R_(b2) as the substituents are eachindependently selected from the group consisting of a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms and a substitutedor unsubstituted aryl group having 6 to 30 ring carbon atoms. R_(b1) andR_(b2) are each independently preferably a substituent selected from thegroup consisting of a substituted or unsubstituted alkyl group having 1to 30 carbon atoms, and a substituted or unsubstituted aryl group having6 to 30 ring carbon atoms, more preferably a substituent selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms.

In the organic EL device of the exemplary embodiment, A is preferably agroup having the partial structure selected from the group consisting ofthe partial structures represented by the respective formulae (a-1),(a-2), (a-3) and (a-5).

In the organic EL device of the exemplary embodiment, B is preferably agroup having the partial structure selected from the group consisting ofthe partial structures represented by the respective formulae (b-2),(b-3) and (b-4).

Examples of a bonding pattern of the compound represented by the formula(1) include bonding patterns shown in Table 1.

TABLE 1 No. a b c d Bonding Pattern (1A) 1 1 0 1 B—A (1B) 1 1 1 1 B—L—A(1C) 2 1 0 1

(1D) 1 2 0 1

(1E) 2 1 1 1

(1F) 1 2 1 1

(1G) 1 1 2 1 B—L—L—A (1H) 1 1 1 2

B of the formula (1) is also preferably represented by a formula (100)below.

In the formula (100), R₁₀₁ to R₁₀₈ each independently represent ahydrogen atom or a substituent.

R₁₀₁ to R₁₀₈ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted aryl group having6 to 30 ring carbon atoms, a substituted or unsubstituted heteroarylgroup having 5 to 30 ring atoms, a substituted or unsubstituted alkylgroup having 1 to 30 carbon atoms, a substituted silyl group, asubstituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, asubstituted or unsubstituted aryloxy group having 6 to 30 ring carbonatoms, a substituted or unsubstituted alkylamino group having 2 to 30carbon atoms, a substituted or unsubstituted arylamino group having 6 to60 ring carbon atoms, a substituted or unsubstituted alkylthio grouphaving 1 to 30 carbon atoms, and a substituted or unsubstituted arylthiogroup having 6 to 30 ring carbon atoms.

In any pair selected from the group consisting of a pair of R₁₀₁ andR₁₀₂, a pair of R₁₀₂ and R₁₀₃, a pair of R₁₀₃ and R₁₀₄, a pair of R₁₀₅and R₁₀₆, a pair of R₁₀₆ and R₁₀₇, and a pair of R₁₀₇ and R₁₀₈, thesubstituents form a saturated or unsaturated ring or do not form a ring.

L₁₀₀ is a linking group selected from linking groups represented byformulae (111) to (117) below.

s is an integer of 0 to 3. A plurality of L₁₀₀ are mutually the same ordifferent.

X₁₀₀ is a linking group selected from linking groups represented byformulae (121) to (125) below.

In the formulae (113) to (117), R₁₀₉ each independently represent thesame as R₁₀₁ to R₁₀₈ of the formula (100).

In the formula (100), one of R₁₀₁ to R₁₀₈ or one of R₁₀₉ is a singlebond to be bonded to L or A in the formula (1).

In a pair of R₁₀₉ and R₁₀₄ of the formula (100) or a pair of R₁₀₉ andR₁₀₅ of the formula (100), the substituents form a saturated orunsaturated ring or do not form a ring.

A plurality of R₁₀₉ are mutually the same or different.

In the formulae (123) to (125), R₁₁₀ each independently represents ahydrogen atom or a substituent.

R₁₁₀ as the substituent is selected from the group consisting of asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, and a substituted or unsubstituted alkyl group having 1 to30 carbon atoms.

A plurality of R₁₁₀ are mutually the same or different.

In a pair of R₁₁₀ and R₁₀₁ of the formula (100) or a pair of R₁₁₀ andR₁₀₈ of the formula (100), the substituents form a saturated orunsaturated ring or do not form a ring.

s in the formula (100) is preferably 0 or 1.

When s is 0 in the formula (100), B in the formula (1) is represented bya formula (100A) below.

X₁₀₀ and R₁₀₁ to R₁₀₈ in the formula (100A) respectively represent thesame as X₁₀₀ and R₁₀₁ to R₁₀₈ in the formula (100).

L₁₀₀ is preferably represented by one of the formulae (111) to (114),more preferably represented by the formula (113) or (114).

X₁₀₀ is preferably represented by one of the formulae (121) to (124),more preferably represented by the formula (123) or (124).

In the organic electroluminescence device of the exemplary embodiment,the first compound is also preferably a compound represented by aformula (11) below.

In the formula (11), Az is a cyclic structure selected from the groupconsisting of a substituted or unsubstituted pyridine ring, asubstituted or unsubstituted pyrimidine ring, a substituted orunsubstituted triazine ring, and a substituted or unsubstituted pyrazinering.

c is an integer of 0 to 5.

When c is 0, Cz and Az are bonded to each other by a single bond.

When c is an integer of 1 to 5, L is a linking group selected from thegroup consisting of a substituted or unsubstituted aryl group having 6to 30 ring carbon atoms, and a substituted or unsubstituted heteroarylgroup having 5 to 30 ring atoms.

When c is an integer of 2 to 5, a plurality of L are mutually the sameor different.

The plurality of L are mutually bonded to form a ring, or not bonded.

Cz is represented by a formula (12) below.

In the formula (12), Y₂₁ to Y₂₈ are each independently a nitrogen atomor CR_(y).

R_(y) each independently represents a hydrogen atom or a substituent.

R_(y) as the substituent is each independently a group selected from thegroup consisting of a substituted or unsubstituted aryl group having 6to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring atoms, a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkylgroup having 1 to 30 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 30 ring carbon atoms, a substituted orunsubstituted aralkyl group having 7 to 30 carbon atoms, a substitutedphosphoryl group, a substituted silyl group, a cyano group, a nitrogroup, and a carboxy group.

A plurality of R_(y) are mutually the same or different.

When a plurality of ones of Y₂₁ to Y₂₈ are CR_(y) and R_(y) is asubstituent, a plurality of R_(y) as the substituents are bonded to eachother to form a ring, or are not bonded.

*1 represents a bonding position with a carbon atom in a structure ofthe linking group represented by L or a bonding position with a carbonatom of the cyclic structure represented by Az.

Y₂₁ to Y₂₈ are also preferably CR_(y).

c in the formula (11) is also preferably 0 or 1.

The compound represented by the formula (11) is also preferably acompound represented by a formula (11A) below.[Formula 71]Cz-L-Az  (11A)

Az, Cz and L in the formula (11A) represent the same as Az, Cz and L inthe formula (11).

L in the formula (11A) is preferably a linking group selected from thegroup consisting of a substituted or unsubstituted aryl group having 6to 30 ring carbon atoms.

The compound represented by the formula (11A) is also preferably acompound represented by a formula (11B) below.

Az and Cz in the formula (11B) represent the same as Az and Cz in theformula (11). c3 is 4. R₁₀ is a hydrogen atom or a substituent. R₁₀ asthe substituent is a substituent selected from the group consisting of asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1to 30 carbon atoms, a substituted or unsubstituted cycloalkyl grouphaving 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkylgroup having 7 to carbon atoms, a substituted phosphoryl group, asubstituted silyl group, a cyano group, a nitro group, and a carboxygroup. A plurality of R₁₀ are the same or different.

The compound represented by the formula (11A) is also preferably acompound represented by a formula (11C) below.

In the formula (11C), Az and Cz represent the same as Az and Cz in theformula (11).

R₄₁ to R₄₄ each independently represent a hydrogen atom or asubstituent.

R₄₁ to R₄₄ as the substituents are each independently a substituentselected from the group consisting of a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms, a substitutedor unsubstituted alkyl group having 1 to 30 carbon atoms, a substitutedor unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 30 ring carbonatoms, a substituted or unsubstituted aralkyl group having 7 to 30carbon atoms, a substituted phosphoryl group, a substituted silyl group,a cyano group, a nitro group, and a carboxy group.

Cz is also preferably represented by a formula (12a), (12b) or (12c)below.

In the formulae (12a), (12b) and (12c), Y₂₁ to Y₂₈ and Y₅₁ to Y₅₈ eachindependently represent a nitrogen atom or CR_(y).

In the formula (12a), at least one of Y₂₅ to Y₂₈ is a carbon atom bondedto one of Y₅₁ to Y₅₄ while at least one of Y₅₁ to Y₅₄ is a carbon atombonded to one of Y₂₅ to Y₂₈.

In the formula (12b), at least one of Y₂₅ to Y₂₈ is a carbon atom bondedto a nitrogen atom in a five-membered ring of a nitrogen-containingfused ring including Y₅₁ to Y₅₈.

In the formula (12c), *a and *b each represent a bonding position withone of Y₂₁ to Y₂₈. At least one of Y₂₅ to Y₂₈ is bonded to the bondingposition represented by *a. At least one of Y₂₅ to Y₂₈ is bonded to thebonding position represented by *b.

n is an integer of 1 to 4.

R_(y) each independently represents a hydrogen atom or a substituent.

R_(y) as the substituent is each independently a substituent selectedfrom the group consisting of a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms, a substituted orunsubstituted fluoroalkyl group having 1 to 30 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 30 ring carbonatoms, a substituted or unsubstituted aralkyl group having 7 to 30carbon atoms, a substituted phosphoryl group, a substituted silyl group,a cyano group, a nitro group, and a carboxy group.

A plurality of R_(y) are mutually the same or different.

When a plurality of ones of Y₂₁ to Y₂₈ are CR_(y) and R_(y) is asubstituent, a plurality of R_(y) are bonded to each other to form aring, or are not bonded.

When a plurality of ones of Y₅₁ to Y₅₈ are CR_(y) and R_(y) is asubstituent, a plurality of R_(y) are bonded to each other to form aring, or are not bonded.

Z₁₁ is one selected from the group consisting of an oxygen atom, asulfur atom, NR₄₅, and CR₄₆R₄₇.

R₄₅ to R₄₇ each independently represent a hydrogen atom or asubstituent.

R₄₅ to R₄₇ as the substituents are each independently a substituentselected from the group consisting of a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms, a substitutedor unsubstituted alkyl group having 1 to 30 carbon atoms, a substitutedor unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 30 ring carbonatoms, a substituted or unsubstituted aralkyl group having 7 to 30carbon atoms, a substituted phosphoryl group, a substituted silyl group,a cyano group, a nitro group, and a carboxy group.

A plurality of R₄₅ are mutually the same or different.

A plurality of R₄₆ are mutually the same or different.

A plurality of R₄₇ are mutually the same or different.

When R₄₆ and R₄₇ are mutually substituents, the substituents are bondedto each other to form a ring, or are not bonded to each other.

* represents a bonding position with a carbon atom in the cyclicstructure represented by Az.

Z₁₁ is preferably NR₄₅.

When Z₁₁ is NR₄₅, R₄₅ is preferably a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms.

Y₅₁ to Y₅₈ are preferably CR_(y). At this time, at least one of Y₅₁ toY₅₈ is a carbon atom bonded to the cyclic structure represented by theformula (12).

Cz is preferably represented by the formula (12c) in which n is 1.

Cz is also preferably represented by a formula (12c-1) below. A grouprepresented by the formula (12c-1) is an exemplary group obtained bybonding Y₂₆ to the bonding position represented by *a and bonding Y₂₇ tothe bonding position represented by *b in the formula (12c).

In the formula (12c-1), Y₂₁ to Y₂₅, Y₂₈, and Y₅₁ to Y₅₄ are eachindependently a nitrogen atom or CR_(y).

R_(y) each independently represents a hydrogen atom or a substituent.

R_(y) as the substituent is each independently a substituent selectedfrom the group consisting of a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms, a substituted orunsubstituted fluoroalkyl group having 1 to 30 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 30 ring carbonatoms, a substituted or unsubstituted aralkyl group having 7 to 30carbon atoms, a substituted phosphoryl group, a substituted silyl group,a cyano group, a nitro group, and a carboxy group.

A plurality of R_(y) are mutually the same or different.

When a plurality of ones of Y₂₁ to Y₂₅ and Y₂₈ are CR_(y) and R_(y) is asubstituent, a plurality of R_(y) are bonded to each other to form aring, or are not bonded.

When a plurality of ones of Y₅₁ to Y₅₄ are CR_(y) and R_(y) is asubstituent, a plurality of R_(y) are bonded to each other to form aring, or are not bonded.

Z₁₁ is one selected from the group consisting of an oxygen atom, asulfur atom, NR₄₅, and CR₄₆R₄₇.

R₄₅ to R₄₇ each independently represent a hydrogen atom or asubstituent.

R₄₅ to R₄₇ as the substituents are each independently a substituentselected from the group consisting of a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms, a substitutedor unsubstituted alkyl group having 1 to 30 carbon atoms, a substitutedor unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 30 ring carbonatoms, a substituted or unsubstituted aralkyl group having 7 to 30carbon atoms, a substituted phosphoryl group, a substituted silyl group,a cyano group, a nitro group, and a carboxy group.

A plurality of R₄₅ are mutually the same or different.

A plurality of R₄₆ are mutually the same or different.

A plurality of R₄₇ are mutually the same or different.

When R₄₆ and R₄₇ are mutually substituents, the substituents are bondedto each other to form a ring, or are not bonded to each other.

* represents a bonding position with a carbon atom in the cyclicstructure represented by Az.

When n is 2 in the formula (12c), Cz is exemplarily represented by aformula (12c-2). When n is 2, two of structures each shown in bracketsadded with an index n are fused to the cyclic structure represented bythe formula (12). Cz represented by the formula (12c-2) is obtained bybonding Y₂₂ to the bonding position represented by *b and bonding Y₂₃ tothe bonding position represented by *a while bonding Y₂₆ to the bondingposition represented by *a and bonding Y₂₇ to the bonding positionrepresented by *b, in the formula (12c).

In the formula (12c-2), Y₂₁, Y₂₄, Y₂₅, Y₂₈, Y₅₁ to Y₅₄, Z₁₁, and *represent the same as Y₂₁, Y₂₄, Y₂₅, Y₂₈, Y₅₁ to Y₅₄, Z₁₁, and * in theformula (12c-1). A plurality of Y₅₁ are mutually the same or different.A plurality of Y₅₂ are mutually the same or different. A plurality ofY₅₃ are mutually the same or different. A plurality of Y₅₄ are mutuallythe same or different. A plurality of Z₁₁ are mutually the same ordifferent.

Az is preferably a cyclic structure selected from the group consistingof a substituted or unsubstituted pyrimidine ring and a substituted orunsubstituted triazine ring.

It is more preferable that Az is a cyclic structure selected from thegroup consisting of a substituted pyrimidine ring and a substitutedtriazine ring, and a substituent for each of the pyrimidine ring and thetriazine ring is selected from the group consisting of a substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms and asubstituted or unsubstituted heteroaryl group having 5 to 30 ring atoms,further preferably a substituted or unsubstituted aryl group having 6 toring carbon atoms.

When the pyrimidine ring and the triazine ring as Az have a substitutedor unsubstituted aryl group as the substituent, the aryl grouppreferably has 6 to 20 ring carbon atoms, more preferably 6 to 14 ringcarbon atoms, further preferably 6 to 12 ring carbon atoms.

When Az has a substituted or unsubstituted aryl group as thesubstituent, the substituent is preferably selected from the groupconsisting of a substituted or unsubstituted phenyl group, a substitutedor unsubstituted biphenyl group, a substituted or unsubstituted naphthylgroup, a substituted or unsubstituted phenanthryl group, a substitutedor unsubstituted terphenyl group, and a substituted or unsubstitutedfluorenyl group, more preferably selected from the group consisting of asubstituted or unsubstituted phenyl group, a substituted orunsubstituted biphenyl group, and a substituted or unsubstitutednaphthyl group.

When Az has a substituted or unsubstituted heteroaryl group as thesubstituent, the substituent is preferably selected from the groupconsisting of a substituted or unsubstituted carbazolyl group, asubstituted or unsubstituted dibenzofuranyl group, and a substituted orunsubstituted dibenzothiophenyl group.

R_(y) is each independently a hydrogen atom or a substituent. R_(y) asthe substituent is preferably selected from the group consisting of asubstituted or unsubstituted aryl group having 6 to 30 ring carbon atomsand a substituted or unsubstituted heteroaryl group having 5 to 30 ringatoms.

When R_(y) as the substituent is a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms, R_(y) as the substituent ispreferably selected from the group consisting of a substituted orunsubstituted phenyl group, a substituted or unsubstituted biphenylgroup, a substituted or unsubstituted naphthyl group, a substituted orunsubstituted phenanthryl group, a substituted or unsubstitutedterphenyl group, and a substituted or unsubstituted fluorenyl group,more preferably selected from the group consisting of a substituted orunsubstituted phenyl group, a substituted or unsubstituted biphenylgroup, and a substituted or unsubstituted naphthyl group.

When R_(y) as the substituent has a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, R_(y) as the substituent ispreferably selected from the group consisting of a substituted orunsubstituted carbazolyl group, a substituted or unsubstituteddibenzofuranyl group, and a substituted or unsubstituteddibenzothiophenyl group.

R₄₅ to R₄₇ as the substituents are each independently preferablyselected from the group consisting of a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms, and asubstituted or unsubstituted alkyl group having 1 to 30 carbon atoms.

The first compound is also preferably a compound represented by aformula (13) below.

In the formula (13), c is 2. a2 is 0 or 1. A plurality of a2 aremutually the same or different. c1 is an integer of 1 to 5. A pluralityof c1 are mutually the same or different. When a2 is 0, R₄₈ and R₄₉ eachindependently represent a hydrogen atom or a monovalent substituent.

R₄₈ and R₄₉ as the substituents are each independently selected from thegroup consisting of a substituted or unsubstituted aryl group having 6to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring atoms, a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted aralkylgroup having 7 to 30 carbon atoms, a substituted or unsubstitutedaryloxy group having 6 to 30 ring carbon atoms, and a substituted silylgroup.

When a2 is 1, R₄₈ and R₄₉ are each independently a linking groupselected from the group consisting of a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms, a substitutedor unsubstituted alkyl group having 1 to 30 carbon atoms, a substitutedor unsubstituted alkoxy group having 1 to 30 carbon atoms, a substitutedor unsubstituted aralkyl group having 7 to 30 carbon atoms, asubstituted or unsubstituted aryloxy group having 6 to 30 ring carbonatoms, and a substituted silyl group.

A plurality of R₄₈ are mutually the same or different.

A plurality of R₄₉ are mutually the same or different.

A₁₁ and A₁₂ are each independently a group having the partial structureselected from the partial structures represented by the formulae (a-1)to (a-7).

A plurality of A₁₂ are mutually the same or different.

L₁₂ represents a single bond or a linking group.

L₁₂ as the linking group is selected from the group consisting of asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, and a substituted or unsubstituted heteroaryl group having 5 to30 ring atoms.

A plurality of L₁₂ are mutually the same or different.

L₁₁ represents a single bond or a linking group.

L₁₁ as the linking group is selected from the group consisting of asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, and a substituted or unsubstituted heteroaryl group having 5 to30 ring atoms.

A plurality of L₁₁ are mutually the same or different.

When a2 is 0 in the formula (13), the first compound is represented by aformula (131) below. c1, c2, A₁₁, L₁₁, L₁₂, R₄₈ and R₄₉ in the formula(131) respectively represent the same as c1, c2, A₁₁, L₁₁, L₁₂, R₄₈ andR₄₉ described above.

In the formula (131), R₄₈ and R₄₉ are preferably a substituent selectedfrom the group consisting of a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms, and a substitutedsilyl group, more preferably a substituent selected from the groupconsisting of a substituted or unsubstituted aryl group having 6 to 30ring carbon atoms, a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring atoms, and a substituted or unsubstituted alkylgroup 1 to 30 carbon atoms.

When a2 is 1 in the formula (13), the first compound is represented by aformula (132) below. c1, c2, A₁₁, A₁₂, L₁₁, L₁₂, R₄₈ and R₄₉ in theformula (132) respectively represent the same as c1, c2, A₁₁, A₁₂, L₁₁,L₁₂, R₄₈ and R₄₉ described above.

In the formula (132), R₄₈ and R₄₉ are preferably a linking groupselected from the group consisting of a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms, and asubstituted silyl group, more preferably a linking group selected fromthe group consisting of a substituted or unsubstituted aryl group having6 to 30 ring carbon atoms and a substituted or unsubstituted heteroarylgroup having 5 to ring atoms.

The first compound is also preferably an exemplary compound representedby a formula (14).

In the formula (14), a1 is 0 or 1. a2 is 0 or 1. a1+a2≥1. c1 is aninteger of 1 to 5.

When a2 is 0, R₄₈ and R₄₉ each independently represent a hydrogen atomor a monovalent substituent.

R₄₈ and R₄₉ as the substituents are each independently selected from thegroup consisting of a substituted or unsubstituted aryl group having 6to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring atoms, a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted aralkylgroup having 7 to 30 carbon atoms, a substituted or unsubstitutedaryloxy group having 6 to 30 ring carbon atoms, and a substituted silylgroup.

When a2 is 1, R₄₈ and R₄₉ are each independently a linking groupselected from the group consisting of a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms, a substitutedor unsubstituted alkyl group having 1 to 30 carbon atoms, a substitutedor unsubstituted alkoxy group having 1 to 30 carbon atoms, a substitutedor unsubstituted aralkyl group having 7 to 30 carbon atoms, asubstituted or unsubstituted aryloxy group having 6 to 30 ring carbonatoms, and a substituted silyl group.

A plurality of R₄₈ are mutually the same or different.

A plurality of R₄₉ are mutually the same or different.

A₁₁ and A₁₂ are each independently a group having the partial structureselected from the partial structures represented by the formulae (a-1)to (a-7).

A plurality of A₁₂ are mutually the same or different.

When a1 is 0, L₁₂ is a hydrogen atom or a monovalent substituent.

L₁₂ as the monovalent substituent is selected from the group consistingof a substituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, and a substituted or unsubstituted heteroaryl group having 5 to30 ring atoms.

When a1 is 1, L₁₂ is a single bond or a linking group.

L₁₂ as the linking group is selected from the group consisting of asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, and a substituted or unsubstituted heteroaryl group having 5 to30 ring atoms.

L₁₁ represents a single bond or a linking group.

L₁₁ as the linking group is selected from the group consisting of asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, and a substituted or unsubstituted heteroaryl group having 5 to30 ring atoms.

A plurality of L₁₁ are mutually the same or different.

The compound represented by the formula (14) is exemplified by acompound represented by a formula (14A).

In the formula (14A), a1, c1, A₁₁, A₁₂, L₁₁ and L₁₂ respectivelyrepresent the same as a1, c1, A₁₁, A₁₂, L₁₁ and L₁₂ in the formula (14).

The compound represented by the formula (13) or (14) is exemplified bycompounds represented by formulae (10B) to (10E).

In the formula (10D), Z_(A) is selected from the group consisting of═N-L₁₁-L₁₂-A₁₁, an oxygen atom, a sulfur atom, and a selenium atom.

In the formulae (10B), (10C), (10D), and (10E), R₄₈, R₄₉, A₁₁, A₁₂, L₁₁,and L₁₂ respectively represent the same as R₄, R₄₉, A₁₁, A₁₂, L₁₁, andL₁₂ in the formula (14).

The compound represented by the formula (131) is also preferably acompound represented by a formula (10F) below.

In the formula (10F), R₄₈, R₄₉, and L₁₁ respectively represent the sameas R₄₈, R₄₉, and L₁₁ in the formula (13). A plurality of R₄₈ aremutually the same or different. A plurality of R₄₉ are mutually the sameor different. A plurality of L₁₁ are mutually the same or different.

Delayed Fluorescence

Delayed fluorescence (thermally activated delayed fluorescence) isdescribed, for instance, on pages 261 to 268 of “Yuki Hando-tai noDebaisu Bussei (Device Physics of Organic Semiconductors)”, edited byADACHI, Chihaya and published by Kodansha Ltd. This literature describesthat, when an energy gap ΔE₁₃ between a singlet state and a tripletstate can be decreased, an inverse energy transfer from the tripletstate to the singlet state, which usually occurs at a low transitionprobability, occurs at a high efficiency to express thermally activateddelayed fluorescence (TADF). Further, an occurrence mechanism of thedelayed fluorescence is described in FIG. 10.38 of this literature. Thefirst compound of the exemplary embodiment is a compound exhibitingthermally activated delayed fluorescence occurring in this mechanism.

Emission of the delayed fluorescence can be checked by measuring thetransient PL (Photo Luminescence).

Behavior of the delayed fluorescence can be analyzed based on the decaycurve obtained by the transient PL measurement. The transient PLmeasurement is a method of measuring decay behavior (transientcharacteristics) of the PL emission after radiating a pulse laser on asample and stopping radiating. The PL emission in the TADF material isclassified into a luminescence component from singlet excitons generatedin first PL excitation and a luminescence component from singletexcitons generated through triplet excitons. A lifetime of the singletexcitons generated in the first PL excitation is very short in ananosecond order. Accordingly, the emission from the singlet excitonsrapidly decays after radiation of the pulse laser.

On the other hand, since delayed fluorescence provides an emission fromsinglet excitons generated through long-life triplet excitons, thedelayed fluorescence gradually decays. Thus, there is a large differencein time between the emission from the singlet excitons generated in thefirst PL excitation and the emission from the singlet excitons throughthe triplet excitons. Accordingly, a luminous intensity derived from thedelayed fluorescence is obtainable

FIG. 2 schematically shows an exemplary device for measuring thetransient PL.

A transient PL measuring device 100 in the exemplary embodimentincludes: a pulse laser 101 capable of radiating a light having apredetermined wavelength; a sample chamber 102 configured to house ameasurement sample; a spectrometer 103 configured to divide a lightradiated from the measurement sample; a streak camera 104 configured toprovide a two-dimensional image; and a personal computer 105 configuredto import and analyze the two-dimensional image. A device for measuringthe transient PL is not limited to the device described in the exemplaryembodiment.

The sample to be housed in the sample chamber 102 is obtained by dopinga matrix material with a doping material at a concentration of 12 mass %and forming a thin film on a quartz substrate.

The thin film sample housed in the sample chamber 102 is radiated with apulse laser from the pulse laser 101 to excite the doping material.Emission is extracted in a direction of 90 degrees with respect to aradiation direction of the excited light. The extracted emission isdivided by the spectrometer 103 to form a two-dimensional image in thestreak camera 104. As a result, the two-dimensional image is obtainablein which the ordinate axis represents a time, the abscissa axisrepresents a wavelength, and a bright spot represents a luminousintensity. When this two-dimensional image is taken out at apredetermined time axis, an emission spectrum in which the ordinate axisrepresents the luminous intensity and the abscissa axis represents thewavelength is obtainable. Moreover, when this two-dimensional image istaken out at the wavelength axis, a decay curve (transient PL) in whichthe ordinate axis represents a logarithm of the luminous intensity andthe abscissa axis represents the time is obtainable.

For instance, a thin film sample A was manufactured as described abovefrom a reference compound H1 as the matrix material and a referencecompound D1 as the doping material and was measured in terms of thetransient PL.

The decay curve was analyzed with respect to the above thin film sampleA and a film sample B. The thin film sample B was manufactured in thesame manner as described above from a reference compound H2 as thematrix material and the reference compound D1 as the doping material.

FIG. 3 shows decay curves obtained from transient PL obtained bymeasuring the thin film samples A and B.

As described above, an emission decay curve in which the ordinate axisrepresents the luminous intensity and the abscissa axis represents thetime can be obtained by the transient PL measurement. Based on theemission decay curve, a fluorescence intensity ratio betweenfluorescence emitted from a singlet state generated by photo-excitationand delayed fluorescence emitted from a singlet state generated byinverse energy transfer via a triplet state can be estimated. In adelayed fluorescent material, a ratio of the intensity of the slowlydecaying delayed fluorescence to the intensity of the promptly decayingfluorescence is relatively large.

In the exemplary embodiment, an emission amount of the delayedfluorescence can be obtained using the device shown in FIG. 2. Promptemission and Delay emission are observed in the first compound. Promptemission is observed promptly when the excited state is achieved byexciting the first compound with a pulse beam (i.e., a beam emitted froma pulse laser) having a wavelength absorbable by the first compound.Delay emission is observed not promptly when the excited state isachieved but after the excited state is achieved. In the exemplaryembodiment, the amount of Delay emission is preferably 5% or morerelative to the amount of Prompt emission. Specifically, provided thatthe amount of Prompt emission is denoted by X_(P) and the amount ofDelay emission is denoted by X_(D), a value of X_(D)/X_(P) is preferably0.05 or more.

The amount of Prompt emission and the amount of Delay emission can beobtained according to the same method as described in “Nature 492,234-238, 2012.” The amount of Prompt emission and the amount of Delayemission may be calculated using a device different from one describedin the above literature.

Moreover, a sample usable for measuring delayed fluorescence isobtained, for instance, by co-depositing the first compound and acompound TH-2 on a quartz substrate at a ratio of the first compound of12 mass % to form a 100-nm-thick thin film.

Manufacturing Method of First Compound

The first compound can be manufactured, for instance, by methodsdescribed in Chemical Communications, p. 10385-10387 (2013) and NATUREPhotonics, p. 326-332 (2014). Moreover, the first compound also can bemanufactured, for instance, by methods disclosed in InternationalPublication No. WO2013/180241, International Publication No.WO2014/092083, International Publication No. WO2014/104346, and thelike. Furthermore, the first compound can be manufactured, for instance,by application of known substitution reactions and/or materialsdepending on a target compound according to reactions described later inExamples.

Specific examples of the first compound of the exemplary embodiment areshown below. The first compound according to the invention is notlimited to these specific examples.

In the organic electroluminescence device of the exemplary embodiment,it is also preferable that the emitting layer contains the firstcompound in a form of a compound represented by a formula (15) below,and the second compound.

This arrangement also can improve a luminous efficiency of an organic ELdevice.

In the formula (15), R₁₅₁ to R₁₆₀ each independently represent ahydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50carbon atoms, a substituted or unsubstituted alkenyl group having 2 to50 carbon atoms, a substituted or unsubstituted alkynyl group having 2to 50 carbon atoms, a substituted or unsubstituted cycloalkyl grouphaving 3 to 50 ring carbon atoms, a substituted or unsubstituted alkoxygroup having 1 to 50 carbon atoms, a substituted or unsubstitutedalkylthio group having 1 to 50 carbon atoms, a substituted orunsubstituted aryloxy group having 6 to 50 ring carbon atoms, asubstituted or unsubstituted arylthio group having 6 to 50 ring carbonatoms, a substituted or unsubstituted aralkyl group having 7 to 50carbon atoms, —Si(R₁₂₁)(R₁₂₂)(R₁₂₃), —C(═O)R₁₂₄, —COOR₁₂₅, a halogenatom, a cyano group, a nitro group, a substituted or unsubstituted arylgroup having 6 to 50 ring carbon atoms, a substituted or unsubstitutedheterocyclic group having 5 to 50 ring atoms, or a group represented by-L₁₀₁-Ar₁₀₁.

In the formula (15), R₁₂₁ to R₁₂₅ each independently represent ahydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50carbon atoms, a substituted or unsubstituted aryl group having 6 to 50ring carbon atoms, or a substituted or unsubstituted heterocyclic grouphaving 5 to 50 ring atoms.

At least one of R₁₅₁ to R₁₆₀ is a group represented by -L₁₀₁-Ar₁₀₁. L₁₀₁represents a single bond, a substituted or unsubstituted arylene grouphaving 6 to ring carbon atoms, or a substituted or unsubstitutedheteroarylene group having to 30 ring atoms. Ar₁₀₁ represents asubstituted or unsubstituted aryl group having 6 to 50 ring carbonatoms, or a substituted or unsubstituted heterocyclic group having 5 to50 ring atoms.

When at least two of L₁₀₁ are present, the at least two of L₁₀₁ may bethe same or different. When at least two of Ar₁₀₁ are present, the atleast two of Ar₁₀₁ may be the same or different.

Among R₁₅₁ to R₁₆₀ in the formula (15), R₁₅₉ and R₁₆₀ are preferablyeach independently a group represented by -L₁₀₁-Ar₁₀₁, and at least oneof R₁₅₉ and R₁₆₀ is preferably a group represented by -L₁₀₁-Ar₁₀₁.

Examples of the compound represented by the formula (15) includecompounds shown below.

Second Compound

The second compound is the compound represented by the formula (2).

The second compound preferably has a main peak wavelength in a rangefrom 430 nm to 480 nm, more preferably in a range from 445 nm to 480 nm.

Herein, the main peak wavelength means a peak wavelength of an emissionspectrum exhibiting a maximum luminous intensity among emission spectrameasured in a toluene solution in which a measurement target compound isdissolved at a concentration ranging from 10⁻⁶ mol/l to 10⁻⁵ mol/l.

The second compound preferably fluoresces blue.

The second compound is preferably a material having a high emissionquantum efficiency.

Molar Absorbance Coefficient

A molar absorbance coefficient of the second compound at an absorptionpeak located closest to the long-wavelength region preferably rangesfrom 29,000 L/(mol·cm) to 1,000,000 L/(mol·cm), more preferably from30,000 L/(mol·cm) to 250,000 L/(mol·cm), further preferably from 40,000L/(mol·cm) to 150,000 L/(mol·cm).

Stokes Shift

The second compound preferably has Stokes shift in a range from 4 nm to18 nm, more preferably in a range from 5 nm to 17 nm.

Relationship Between First Compound and Second Compound in EmittingLayer

When the first compound is a delayed fluorescent compound, a singletenergy S₁(M1) of the first compound and a singlet energy S₁(M2) of thesecond compound preferably satisfy a relationship of the followingnumerical formula (Numerical Formula 1).S ₁(M1)>S ₁(M2)  (Numerical Formula 1).

An energy gap T_(77K)(M1) at 77 [K] of the first compound is preferablylarger than an energy gap T_(77K)(M2) at 77 [K] of the second compound.In other words, a relationship of the following numerical formula(Numerical Formula 4) is preferably satisfied.T _(77K)(M1)>T _(77K)(M2)  (Numerical Formula 4).

When the organic EL device 1 of the exemplary embodiment emits light, itis preferable that the second compound in the emitting layer 5 mainlyemits light.

Relationship Between Triplet Energy and Energy Gap at 77K

Here, a relationship between a triplet energy and an energy gap at 77Kwill be described. In the exemplary embodiment, the energy gap at 77 [K]is different from a typical triplet energy in some aspects.

Triplet energy is measured as follows. Firstly, a solution in which acompound (measurement target) is dissolved in an appropriate solvent isencapsulated in a quartz glass tube to prepare a sample. Aphosphorescent spectrum (ordinate axis: phosphorescent luminousintensity, abscissa axis: wavelength) of the sample is measured at a lowtemperature (77K). A tangent is drawn to the rise of the phosphorescentspectrum close to the short-wavelength region. The triplet energy iscalculated by a predetermined conversion equation based on a wavelengthvalue at an intersection of the tangent and the abscissa axis.

Here, the delayed fluorescent compound used in the exemplary embodimentis preferably a compound having a small ΔST. When ΔST is small,intersystem crossing and inverse intersystem crossing are likely tooccur even at a low temperature (77K), so that the singlet state and thetriplet state coexist. As a result, the spectrum to be measured in thesame manner as the above includes emission from both the singlet stateand the triplet state. Although it is difficult to distinguish theemission from the singlet state from the emission from the tripletstate, the value of the triplet energy is basically considered dominant.

Accordingly, in the exemplary embodiment, the triplet energy is measuredby the same method as a typical triplet energy T, but a value measuredin the following manner is referred to as an energy gap T_(77K) in orderto differentiate the measured energy from the typical triplet energy ina strict meaning. The measurement target compound is dissolved in EPA(diethylether:isopentane:ethanol=5:5:2 in volume ratio) at aconcentration of 10 μmol/L, and the obtained solution is encapsulated ina quartz cell to provide a measurement sample. A phosphorescent spectrum(ordinate axis: phosphorescent luminous intensity, abscissa axis:wavelength) of the sample is measured at a low temperature (77K). Atangent is drawn to the rise of the phosphorescent spectrum close to theshort-wavelength region. An energy amount is calculated as the energygap T_(77K) at 77K according to a conversion equation (F1) below basedon a wavelength value λ_(edge) (nm) at an intersection of the tangentand the abscissa axis.T _(77K) [eV]=1239.85/λ_(edge)  Conversion Equation (F1):

The tangent to the rise of the phosphorescence spectrum close to theshort-wavelength region is drawn as follows. While moving on a curve ofthe phosphorescence spectrum from the short-wavelength region to themaximum spectral value closest to the short-wavelength region among themaximum spectral values, a tangent is checked at each point on the curvetoward the long-wavelength of the phosphorescence spectrum. Aninclination of the tangent is increased along the rise of the curve(i.e., a value of the ordinate axis is increased). A tangent drawn at apoint of the maximum inclination (i.e., a tangent at an inflectionpoint) is defined as the tangent to the rise of the phosphorescencespectrum close to the short-wavelength region.

The maximum with peak intensity being 15% or less of the maximum peakintensity of the spectrum is not included in the above-mentioned maximumclosest to the short-wavelength region. The tangent drawn at a point ofthe maximum spectral value being closest to the short-wavelength regionand having the maximum inclination is defined as a tangent to the riseof the phosphorescence spectrum close to the short-wavelength region.

For phosphorescence measurement, a spectrophotofluorometer body F-4500(manufactured by Hitachi High-Technologies Corporation) is usable. Anydevice for phosphorescence measurement is usable. A combination of acooling unit, a low temperature container, an excitation light sourceand a light-receiving unit may be used for phosphorescence measurement.

Singlet Energy S₁

A method of measuring a singlet energy S₁ with use of a solution(occasionally referred to as a solution method) is exemplified by amethod below.

A 10-μmol/L toluene solution of a compound (measurement target) isprepared and put in a quartz cell to prepare a sample. An absorptionspectrum (ordinate axis: luminous intensity, abscissa axis: wavelength)of the sample is measured at a normal temperature (300K). A tangent isdrawn to the fall of the absorption spectrum close to thelong-wavelength region, and a wavelength value λedge (nm) at anintersection of the tangent and the abscissa axis is obtained. Thewavelength value λedge (nm) is substituted in a conversion equation (F2)below to calculate a singlent energy.S ₁ [eV]=1239.85/λedge  Conversion Equation (F2):

Any device for measuring absorption spectrum is usable. For instance, aspectrophotometer (U3310 manufactured by Hitachi, Ltd.) is usable.

The tangent to the fall of the absorption spectrum close to thelong-wavelength region is drawn as follows. While moving on a curve ofthe absorption spectrum from the maximum spectral value closest to thelong-wavelength region in a long-wavelength direction, a tangent at eachpoint on the curve is checked. An inclination of the tangent isdecreased and increased in a repeated manner as the curve falls (i.e., avalue of the ordinate axis is decreased). A tangent drawn at a point ofthe minimum inclination closest to the long-wavelength region (exceptwhen absorbance is 0.1 or less) is defined as the tangent to the fall ofthe absorption spectrum close to the long-wavelength region.

The maximum absorbance of 0.2 or less is not included in theabove-mentioned maximum absorbance close to the long-wavelength region.

Content Ratios of Compounds in Emitting Layer

Content ratios of the respective first and second compounds in theemitting layer 5 preferably range as follows.

The content ratio of the first compound preferably ranges from 90 mass %to 99.9 mass %, more preferably from 95 mass % to 99.9 mass %, furtherpreferably from 99 mass % to 99.9 mass %.

The content ratio of the second compound preferably ranges from 0.01mass % to 10 mass %, more preferably from 0.01 mass % to 5 mass %,further preferably from 0.01 mass % to 1 mass %.

It should be noted that the emitting layer 5 of the exemplary embodimentmay contain a material other than the first compound and the secondcompound.

Thickness of Emitting Layer

A thickness of the emitting layer 5 preferably ranges from 5 nm to 50nm, more preferably from 7 nm to 50 nm, further preferably from 10 nm to50 nm. The emitting layer 5 having the thickness of 5 nm or more iseasily formable and easily adjustable in chromaticity. The emittinglayer 5 having the thickness of 50 nm or less can restrain a rise in thedrive voltage.

TADF Mechanism

FIG. 4 shows an example of a relationship between energy levels of thefirst compound and the second compound in the emitting layer. In FIG. 4,S0 represents a ground state. S1(M1) represents the lowest singlet stateof the first compound. T1(M1) represents the lowest triplet state of thefirst compound. S1(M2) represents the lowest singlet state of the secondcompound. T1(M2) represents the lowest triplet state of the secondcompound.

A dashed arrow directed from S1(M1) to S1(M2) in FIG. 4 representsForster energy transfer from the lowest singlet state of the firstcompound to the lowest singlet state of the second compound.

As shown in FIG. 4, when a compound having a small ΔST(M1) is used asthe first compound, inverse intersystem crossing from the lowest tripletstate T1(M1) to the lowest singlet state S1(M1) can be caused by a heatenergy. Subsequently, Forster energy transfer from the lowest singletstate S1(M1) of the first compound the second compound occurs togenerate the lowest singlet state S1(M2). Consequently, fluorescencefrom the lowest singlet state S1(M2) of the second compound can beobserved. It is inferred that the internal quantum efficiency can betheoretically raised up to 100% also by using delayed fluorescence bythe TADF mechanism.

Substrate

The substrate 2 is used as a support for the organic EL device 1. Forinstance, glass, quartz, plastics and the like are usable as thesubstrate 2. A flexible substrate is also usable. The flexible substrateis a bendable substrate, which is exemplified by a plastic substrate.Examples of a material for forming the plastic substrate includepolycarbonate, polyarylate, polyethersulfone, polypropylene, polyester,polyvinyl fluoride, polyvinyl chloride, polyimide, and polyethylenenaphthalate. Moreover, an inorganic vapor deposition film is alsousable.

Anode

Metal having a large work function (specifically, 4.0 eV or more),alloy, an electrically conductive compound and a mixture thereof arepreferably usable as the anode 3 formed on the substrate 2. Specificexamples of the material for the anode include indium tin oxide (ITO),indium tin oxide containing silicon or silicon oxide, indium zinc oxide,tungsten oxide, indium oxide containing zinc oxide and graphene. Inaddition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chrome(Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium(Pd), titanium (Ti), nitrides of these metal materials (e.g., titaniumnitride) and the like are usable.

The above materials are typically formed into a film by sputtering. Forinstance, a target of the indium zinc oxide which is prepared by addingzinc oxide in a range from 1 mass % to 10 mass % relative to indiumoxide is used for forming a film by sputtering. Moreover, for instance,as for the indium oxide containing tungsten oxide and zinc oxide, atarget thereof prepared by adding tungsten oxide in a range from 0.5mass % to 5 mass % and zinc oxide in a range from 0.1 mass % to 1 mass %relative to indium oxide is usable for forming a film by sputtering. Inaddition, vapor deposition, coating, ink jet printing, spin coating andthe like may be used for forming a film.

Among the organic layers formed on the anode 3, the hole injecting layer6 formed adjacent to the anode 3 is formed of a composite material inwhich holes are easily injectable irrespective of the work function ofthe anode 3. Accordingly, other materials usable as an electrodematerial (e.g., a metal, alloy, electrically conductive compound,mixture thereof, and elements belonging to Group 1 or 2 in the periodictable of the elements) are also usable for the anode 3.

A material having a small work function such as elements belonging toGroups 1 and 2 in the periodic table of the elements, a rare earth metaland an alloy including the elements and/or the rare earth metal are alsousable for the anode 3. Examples of the elements belonging to Group 1 inthe periodic table of the elements include an alkali metal. Examples ofthe elements belonging to Group 2 in the periodic table of the elementsinclude an alkaline earth metal. Examples of the alkali metal includelithium (Li) and cesium (Cs). Examples of the alkaline earth metalinclude magnesium (Mg), calcium (Ca) and strontium (Sr). Examples of therare earth metal include europium (Eu) and ytterbium (Yb). Examples ofthe alloy include MgAg and AlLi.

When the cathode 3 is formed of the alkali metal, alkaline earth metaland alloys thereof, vapor deposition and sputtering are usable.Moreover, when the cathode 4 is formed of silver paste and the like,coating, ink jet printing and the like are usable.

Hole Injecting Layer

The hole injecting layer 6 is a layer containing a highlyhole-injectable substance. Examples of the highly hole-injectablesubstance include molybdenum oxide, titanium oxide, vanadium oxide,rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafniumoxide, tantalum oxide, silver oxide, tungsten oxide, and manganeseoxide.

In addition, the examples of the highly hole-injectable substancefurther include: an aromatic amine compound, which is a low-moleculecompound, such that 4,4′,4″-tris(N,N-diphenylamino)triphenylamine(abbreviation: TDATA),4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine(abbreviation: MTDATA),4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl(abbreviation:DPAB),4,4′-bis(N-{4-[N′-(3-methylphenyl)-N′-phenylamino]phenyl}-N-phenylamino)biphenyl(abbreviation: DNTPD),1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene(abbreviation: DPA3B),3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA1),3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA2), and3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole(abbreviation: PCzPCN1); anddipyrazino[2,3-f:20,30-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile(HAT-CN).

Moreover, a macromolecular compound is also usable as the highlyhole-injectable substance. Examples of the macromolecular compoundinclude an oligomer, dendrimer and polymer. Specific examples of themacromolecular compound include poly(N-vinylcarbazole) (abbreviation:PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA),poly[N-(4-{N′-[4-(4-diphenylamino)phenyl]phenyl-N′-phenylamino}phenyl)methacrylamido](abbreviation:PTPDMA), and poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine](abbreviation: Poly-TPD). Moreover, the examples of the macromolecularcompound include a macromolecular compound added with an acid such aspoly(3,4-ethylene dioxythiophene)/poly(styrene sulfonic acid)(PEDOT/PSS), and polyaniline/poly(styrene sulfonic acid) (PAni/PSS).

Hole Transporting Layer

The hole transporting layer 7 is a layer containing a highlyhole-transporting substance. For instance, an aromatic amine compound,carbazole derivative, anthracene derivative and the like are usable forthe hole transporting layer 7. Specifically, for instance, an aromaticamine compound is usable for the hole transporting layer. Examples ofthe aromatic amine compound include4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB),N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(abbreviation: TPD), 4-phenyl-4′-(9-phenylfluorene-9-yl)triphenylamine(abbreviation: BAFLP),4,4′-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl(abbreviation: DFLDPBi), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine(abbreviation: TDATA),4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine(abbreviation: MTDATA), and4,4′-bis[N-(spiro-9,9′-bifluorene-2-yl)-N-phenylamino]biphenyl(abbreviation: BSPB). The above-described substances mostly have a holemobility of 10⁻⁶ cm²/(Vs) or more. A carbazole derivative (e.g., CBP,9-[4-(N-carbazolyl)]phenyl-10-phenylanthracene (CzPA), and9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (PCzPA)) and ananthracene derivative (e.g., t-BuDNA, DNA, and DPAnth) may be used forthe hole transporting layer 7. Moreover, a macromolecular compound suchas poly(N-vinylcarbazole) (abbreviation: PVK) andpoly(4-vinyltriphenylamine) (abbreviation: PVTPA) is also usable for thehole transporting layer 6.

However, any substance having a hole transporting performance higherthan an electron transporting performance may be used in addition to theabove substances. A layer including the highly hole-transportingsubstance may be provided in the form of a single layer or a laminate oftwo or more layers.

When the hole transporting layer includes two or more layers, one of thelayers with a larger energy gap is preferably provided closer to theemitting layer 5.

Electron Transporting Layer

The electron transporting layer 8 is a layer containing a highlyelectron-transporting substance. For the electron transporting layer 8,(1) a metal complex such as an aluminum complex, beryllium complex andzinc complex, (2) heteroaromatic compound such as an imidazolederivative, benzimidazole derivative, azine derivative, carbazolederivative, and phenanthroline derivative, and (3) a macromolecularcompound are usable. Specifically, as a low-molecule organic compound, ametal complex such as Alq, tris(4-methyl-8-quinolinolato)aluminum(abbreviation: Almq₃), bis(10-hydroxybenzo[h]quinolinato)beryllium(abbreviation: BeBq₂), BAlq, Znq, ZnPBO and ZnBTZ are usable. Inaddition to the metal complex, a heteroaromatic compound such as2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation:PBD), 1,3-bis[5-(ptert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene(abbreviation: OXD-7),3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenylyl)-1,2,4-triazole(abbreviation: TAZ),3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole(abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen),bathocuproine (abbreviation: BCP), and4,4′-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviation: BzOs) areusable. In the exemplary embodiments, a benzimidazole compound issuitably usable. The above-described substances mostly have an electronmobility of 10⁻⁶ cm²/(V·s) or more. However, any substance having anelectron transporting performance higher than a hole transportingperformance may be used for the electron transporting layer 8 inaddition to the above substances. The electron transporting layer 8 maybe provided in the form of a single layer or a laminate of two or morelayers made of the above substance(s).

Moreover, a macromolecular compound is also usable for the electrontransporting layer 8. For instance,poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)](abbreviation: PF-Py),poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)](abbreviation:PF-BPy) and the like are usable.

Electron Injecting Layer

The electron injecting layer 9 is a layer containing a highlyelectron-injectable substance. Examples of a material for the electroninjecting layer 9 include an alkali metal, alkaline earth metal and acompound thereof, examples of which include lithium (Li), cesium (Cs),calcium (Ca), lithium fluoride (LiF), cesium fluoride (CsF), calciumfluoride (CaF2), and lithium oxide (LiOx). In addition, a substancecontaining an alkali metal, alkaline earth metal and a compound thereofin the electron-transporting substance, specifically, a substancecontaining magnesium (Mg) in Alq may be used. In this case, electronscan be more efficiently injected from the cathode 4.

Alternatively, a composite material provided by mixing an organiccompound with an electron donor may be used for the electron injectinglayer 9. The composite material exhibits excellent electron injectingperformance and electron transporting performance since the electrondonor generates electron in the organic compound. In this arrangement,the organic compound is preferably a material exhibiting an excellenttransforming performance of the generated electrons. Specifically, forinstance, the above-described substance for the electron transportinglayer 8 (e.g., the metal complex and heteroaromatic compound) is usable.The electron donor may be any substance exhibiting an electron donatingperformance to the organic compound. Specifically, an alkali metal, analkaline earth metal or a rare earth metal is preferable, examples ofwhich include lithium, cesium, magnesium, calcium, erbium and ytterbium.Moreover, an alkali metal oxide and alkaline earth metal oxide arepreferably used as the electron donor, examples of which include lithiumoxide, calcium oxide, and barium oxide. Further, Lewis base such asmagnesium oxide is also usable. Furthermore, tetrathiafulvalene(abbreviation: TTF) is also usable.

Cathode

Metal, alloy, an electrically conductive compound, a mixture thereof andthe like, which have a small work function, specifically, of 3.8 eV orless, is preferably usable as a material for the cathode 4. Specificexamples of the material for the cathode include the elements belongingto Groups 1 and 2 in the periodic table of the elements, a rare-earthmetal and an alloy including the elements and/or the rare-earth metal.Examples of the elements belonging to Group 1 in the periodic table ofthe elements include an alkali metal. Examples of the elements belongingto Group 2 in the periodic table of the elements include an alkalineearth metal. Examples of the alkali metal include lithium (Li) andcesium (Cs). Examples of the alkaline earth metal include magnesium(Mg), calcium (Ca) and strontium (Sr). Examples of the rare earth metalinclude europium (Eu) and ytterbium (Yb). Examples of the alloy includeMgAg and AlLi.

When the cathode 4 is formed of the alkali metal, alkaline earth metaland alloy thereof, vapor deposition and sputtering are usable. Moreover,when the cathode 4 is formed of silver paste and the like, coating, inkjet printing and the like are usable.

By providing the electron injecting layer 9, various conductivematerials such as Al, Ag, ITO, graphene and indium oxide-tin oxidecontaining silicon or silicon oxide are usable for forming the cathode 4irrespective of the magnitude of the work function. The conductivematerials can be deposited as a film by sputtering, ink jet printing,spin coating and the like.

Layer Formation Method(s)

A method for forming each layer of the organic EL device in the firstexemplary embodiment is not limited except for the above particulardescription. Known methods of dry film-forming and wet film-forming areusable. Examples of the dry film-forming include vacuum deposition,sputtering, plasma deposition method and ion plating. Examples of thewet film-forming include spin coating, dipping, flow coating andink-jet.

Thickness

A thickness of each of the organic layers in the organic EL device 1according to the first exemplary embodiment is not limited except forthe above particular description. In general, the thickness preferablyranges from several nanometers to 1 μm in order to avoid defects such asa pin hole and to prevent efficiency from being deteriorated since ahigh voltage needs to be applied.

Herein, the number of carbon atoms forming a ring (also referred to asring carbon atoms) means the number of carbon atoms included in atomsforming the ring itself of a compound in which the atoms are bonded toform the ring (e.g., a monocyclic compound, a fused ring compound, across-linked compound, a carbocyclic compound, and a heterocycliccompound). When the ring is substituted by a substituent, the “ringcarbon atoms” do not include carbon(s) contained in the substituent.Unless specifically described, the same applies to the “ring carbonatoms” described later. For instance, a benzene ring has 6 ring carbonatoms, a naphthalene ring has 10 ring carbon atoms, a pyridinyl grouphas 5 ring carbon atoms, and a furanyl group has 4 ring carbon atoms.When the benzene ring and/or the naphthalene ring is substituted by, forinstance, an alkyl group, the number of carbon atoms of the alkyl groupis not included in the number of the ring carbon atoms. When a fluorenering is substituted by, for instance, a fluorene ring (e.g., aspirofluorene ring), the number of carbon atoms of the fluorene ring asa substituent is not counted in the number of the ring carbon atoms forthe fluorene ring.

Herein, the number of atoms forming a ring (also referred to as ringatoms) means the number of atoms forming the ring itself of a compoundin which the atoms are bonded to form the ring (e.g., a monocycliccompound, a fused ring compound, a cross-linked compound, a carbocycliccompound, and a heterocyclic compound). Atom(s) not forming the ring(e.g., a hydrogen atom for terminating the atoms forming the ring) andatoms included in a substituent substituting the ring are not counted inthe number of the ring atoms. Unless specifically described, the sameapplies to the “ring atoms” described later. For instance, a pyridinering has 6 ring atoms, a quinazoline ring has 10 ring atoms, and a furanring has 5 ring atoms. Hydrogen atoms respectively bonded to carbonatoms of the pyridine ring and the quinazoline ring and atoms formingthe substituents are not counted in the number of the ring atoms. When afluorene ring is substituted by, for instance, a fluorene ring(inclusive of a spirofluorene ring), the number of atoms of the fluorenering as a substituent is not included in the number of the ring atomsfor the fluorene ring.

Next, each of substituents described in the above formulae will bedescribed.

Examples of the aryl group (occasionally, referred to as aromatichydrocarbon group) having 6 to 30 ring carbon atoms or the aryl grouphaving 6 to 50 ring carbon atoms include a phenyl group, biphenyl group,terphenyl group, naphthyl group, anthryl group, phenanthryl group,fluorenyl group, pyrenyl group, chrysenyl group, fluoranthenyl group,benz[a]anthryl group, benzo[c]phenanthryl group, triphenylenyl group,benzo[k]fluoranthenyl group, benzo[g]chrysenyl group,benzo[b]triphenylenyl group, picenyl group, and perylenyl group.

Herein, the aryl group preferably has 6 to 20 ring carbon atoms, morepreferably 6 to 14 ring carbon atoms, further preferably 6 to 12 ringcarbon atoms. Among the aryl group, a phenyl group, biphenyl group,naphthyl group, phenanthryl group, terphenyl group and fluorenyl groupare particularly preferable. A carbon atom in a position 9 of each of1-fluorenyl group, 2-fluorenyl group, 3-fluorenyl group and 4-fluorenylgroup is preferably substituted by a substituted or unsubstituted alkylgroup having 1 to 30 carbon atoms or a substituted or unsubstituted arylgroup having 6 to 18 ring carbon atoms described later herein.

Herein, the heteroaryl group (occasionally, referred to as aheterocyclic group, heteroaromatic ring group or aromatic heterocyclicgroup) having 5 to 30 ring atoms or the heterocyclic group having 5 to50 ring atoms preferably contains as a hetero atom at least one atomselected from the group consisting of nitrogen, sulfur, oxygen, silicon,selenium atom and germanium atom, and more preferably contains at leastone atom selected from the group consisting of nitrogen, sulfur andoxygen.

Herein, examples of the heterocyclic group having 5 to 30 ring atoms orthe heterocyclic group having 5 to 50 ring atoms are a pyridyl group,pyrimidinyl group, pyrazinyl group, pyridazynyl group, triazinyl group,quinolyl group, isoquinolinyl group, naphthyridinyl group, phthalazinylgroup, quinoxalinyl group, quinazolinyl group, phenanthridinyl group,acridinyl group, phenanthrolinyl group, pyrrolyl group, imidazolylgroup, pyrazolyl group, triazolyl group, tetrazolyl group, indolylgroup, benzimidazolyl group, indazolyl group, imidazopyridinyl group,benzotriazolyl group, carbazolyl group, furyl group, thienyl group,oxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group,oxadiazolyl group, thiadiazolyl group, benzofuranyl group,benzothiophenyl group, benzoxazolyl group, benzothiazolyl group,benzisoxazolyl group, benzisothiazolyl group, benzoxadiazolyl group,benzothiadiazolyl group, dibenzofuranyl group, dibenzothiophenyl group,piperidinyl group, pyrrolidinyl group, piperazinyl group, morpholylgroup, phenazinyl group, phenothiazinyl group, and phenoxazinyl group.

Herein, the heterocyclic group preferably has 5 to 20 ring atoms, morepreferably 5 to 14 ring atoms. Among the above heterocyclic group, a1-dibenzofuranyl group, 2-dibenzofuranyl group, 3-dibenzofuranyl group,4-dibenzofuranyl group, 1-dibenzothiophenyl group, 2-dibenzothiophenylgroup, 3-dibenzothiophenyl group, 4-dibenzothiophenyl group,1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolylgroup, and 9-carbazolyl group are further preferable. A nitrogen atom inposition 9 of 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl groupand 4-carbazolyl group is preferably substituted by the substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms or thesubstituted or unsubstituted heterocyclic group having 5 to 30 ringatoms described herein.

Herein, the heterocyclic group may be a group derived from any one ofpartial structures represented by formulae (XY-1) to (XY-18).

In the formulae (XY-1) to (XY-18), X_(A) and Y_(A) each independentlyrepresent a hetero atom, and preferably represent an oxygen atom, sulfuratom, selenium atom, silicon atom or germanium atom. The partialstructures represented by the formulae (XY-1) to (XY-18) may each bebonded in any position to be a heterocyclic group, which may besubstituted.

Herein, examples of the substituted or unsubstituted carbazolyl groupmay include a group as represented by formulae below in which acarbazole ring is further fused with a ring(s). Such a group also may besubstituted. A bonding position is alterable as desired.

The alkyl group having 1 to 30 carbon atoms or the alkyl group having 1to 50 carbon atoms may be linear, branched or cyclic. Also, the alkylgroup may be an alkyl halide group.

Examples of the linear or branched alkyl group include: a methyl group,ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butylgroup, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group,n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecylgroup, n-dodecyl group, n-tridecyl group, n-tetradecyl group,n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecylgroup, neopentyl group, amyl group, isoamyl group, 1-methylpentyl group,2-methylpentyl group, 1-pentylhexyl group, 1-butylpentyl group,1-heptyloctyl group, and 3-methylpentyl group.

Herein, the linear or branched alkyl group preferably has 1 to 10 carbonatoms, more preferably 1 to 6 carbon atoms. Among the linear or branchedalkyl group, a methyl group, ethyl group, propyl group, isopropyl group,n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentylgroup, n-hexyl group, amyl group, isoamyl group and neopentyl group arepreferable.

Herein, examples of the cyclic alkyl group include a cycloalkyl grouphaving 3 to 30 ring carbon atoms or a cycloalkyl group having 3 to 50ring carbon atoms.

Herein, examples of the cycloalkyl group having 3 to 30 ring carbonatoms or the cycloalkyl group having 3 to 50 ring carbon atoms include acyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexylgroup, 4-metylcyclohexyl group, adamantyl group and norbornyl group. Thecycloalkyl group preferably has 3 to 10 ring carbon atoms, morepreferably 5 to 8 ring carbon atoms. Among the cycloalkyl group, acyclopentyl group and a cyclohexyl group are further preferable.

Herein, the alkyl halide group provided by substituting the alkyl groupwith a halogen atom is exemplified by an alkyl halide group provided bysubstituting the alkyl group having 1 to 30 carbon atoms with at leastone halogen atom, preferably at least one fluorine atom.

Herein, examples of the alkyl halide group having 1 to 30 carbon atomsinclude a fluoromethyl group, difluoromethyl group, trifluoromethylgroup, fluoroethyl group, trifluoromethylmethyl group, trifluoroethylgroup, and pentafluoroethyl group.

Herein, examples of a substituted silyl group include an alkylsilylgroup having 3 to 30 carbon atoms and an arylsilyl group having 6 to 30ring carbon atoms.

Herein, the alkylsilyl group having 3 to 30 carbon atoms is exemplifiedby a trialkylsilyl group having the above examples of the alkyl grouphaving 1 to 30 carbon atoms. Specific examples of the alkylsilyl groupare a trimethylsilyl group, triethylsilyl group, tri-n-butylsilyl group,tri-n-octylsilyl group, triisobutylsilyl group, dimethylethylsilylgroup, dimethylisopropylsilyl group, dimethyl-n-propylsilyl group,dimethyl-n-butylsilyl group, dimethyl-t-butylsilyl group,diethylisopropylsilyl group, vinyl dimethylsilyl group,propyldimethylsilyl group, and triisopropylsilyl group. Three alkylgroups in the trialkylsilyl group may be mutually the same or different.

Herein, examples of the arylsilyl group having 6 to 30 ring carbon atomsinclude a dialkylarylsilyl group, alkyldiarylsilyl group andtriarylsilyl group.

The dialkylarylsilyl group is exemplified by a dialkylarylsilyl groupincluding two of the examples of the alkyl group having 1 to 30 carbonatoms and one of the examples of the aryl group having 6 to 30 ringcarbon atoms. The dialkylarylsilyl group preferably has 8 to 30 carbonatoms.

The alkyldiarylsilyl group is exemplified by an alkyldiarylsilyl groupincluding one of the examples of the alkyl group having 1 to 30 carbonatoms and two of the examples of the aryl group having 6 to 30 ringcarbon atoms. The alkyldiarylsilyl group preferably has 13 to 30 carbonatoms.

The triarylsilyl group is exemplified by a triarylsilyl group includingthree of the examples of the aryl group having 6 to 30 ring carbonatoms. The triarylsilyl group preferably has 18 to 30 carbon atoms.

Herein, an aryl group in an aralkyl group (occasionally referred to asan arylalkyl group) is an aromatic hydrocarbon group or a heterocyclicgroup.

Herein, the aralkyl group having 7 to 30 carbon atoms is preferably agroup having an aryl group having 6 to 30 ring carbon atoms, and thearalkyl group having 7 to 50 carbon atoms is preferably a group havingan aryl group having 6 to 50 ring carbon atoms. Each of the aralkylgroups is represented by —Z₃-Z₄. Z₃ is exemplified by an alkylene groupderived from the above alkyl group having 1 to 30 carbon atoms or alkylgroup having 1 to 50 carbon atoms. Z₄ is exemplified by the above arylgroup having 6 to 30 ring carbon atoms or aryl group having 6 to 50 ringcarbon atoms. In this aralkyl group, an aryl moiety has 6 to 30 carbonatoms, preferably 6 to 20 carbon atoms, more preferably 6 to 12 carbonatoms and an alkyl moiety has 1 to 30 carbon atoms, preferably 1 to 20carbon atoms, more preferably 1 to 10 carbon atoms, further preferably 1to 6 carbon atoms. Examples of the aralkyl group are a benzyl group,2-phenylpropane-2-yl group, 1-phenylethyl group, 2-phenylethyl group,1-phenylisopropyl group, 2-phenylisopropyl group, phenyl-t-butyl group,α-naphthylmethyl group, 1-α-naphthylethyl group, 2-α-naphthylethylgroup, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group,β-naphthylmethyl group, 1-β-naphthylethyl group, 2-β-naphthylethylgroup, 1-β-naphthylisopropyl group, and 2-β-naphthylisopropyl group.

Herein, the substituted phosphoryl group is represented by a formula (P)below.

In the formula (P), Ar_(P1) and Ar_(P2) are each independently asubstituent, preferably a substituent selected from the group consistingof an alkyl group having 1 to 30 carbon atoms and an aryl group having 6to 30 ring carbon atoms, more preferably a substituent selected from thegroup consisting of an alkyl group having 1 to 10 carbon atoms and anaryl group having 6 to 20 ring carbon atoms, further preferably asubstituent selected from the group consisting of an alkyl group having1 to 6 carbon atoms and an aryl group having 6 to 14 ring carbon atoms.

Herein, the alkoxy group having 1 to 30 carbon atoms or the alkoxy grouphaving 1 to 50 carbon atoms is represented by —OZ₁. Z₁ is exemplified byan alkyl group having 1 to 30 carbon atoms or an alkyl group having 1 to50 carbon atoms. Examples of the alkoxy group include a methoxy group,ethoxy group, propoxy group, butoxy group, pentyloxy group and hexyloxygroup. The alkoxy group preferably has 1 to 20 carbon atoms.

A halogenated alkoxy group provided by substituting the alkoxy groupwith a halogen atom is exemplified by a halogenated alkoxy groupprovided by substituting the alkoxy group having 1 to 30 carbon atomswith one or more fluorine groups.

Herein, examples of an aryl group in an aryloxy group (occasionallyreferred to as an arylalkoxy group) include a heteroaryl group.

Herein, the aryloxy group of the arylalkoxy group having 6 to 30 ringcarbon atoms or the arylalkoxy group having 6 to 50 ring carbon atoms isrepresented by —OZ₂. Z₂ is exemplified by the above aryl group having 6to 30 ring carbon atoms or aryl group having 6 to 50 ring carbon atoms.The arylalkoxy group preferably has 6 to 20 ring carbon atoms. Thearylalkoxy group is exemplified by a phenoxy group.

Herein, the substituted amino group is represented by —NHR_(V) or—N(R_(V))₂. R_(V) is exemplified by the above alkyl group having 1 to 30carbon atoms or aryl group having 6 to 30 ring carbon atoms.

Herein, the alkenyl group having 2 to 30 carbon atoms or the alkenylgroup having 2 to 50 carbon atoms is linear or branched. Examples of thealkenyl group include a vinyl group, propenyl group, butenyl group,oleyl group, eicosapentaenyl group, docosahexaenyl group, styryl group,2,2-diphenylvinyl group, 1,2,2-triphenylvinyl group, and2-phenyl-2-propenyl group.

Herein, the alkynyl group having 2 to 30 carbon atoms or the alkynylgroup having 2 to 50 carbon atoms may be linear or branched. Examples ofthe alkynyl group include ethynyl, propynyl and 2-phenylethynyl.

Herein, the substituted phosphanyl group is exemplified by a phenylphosphanyl group.

Herein, the arylcarbonyl group having 6 to 30 ring carbon atoms isrepresented by —COOY′. Y′ is exemplified by the above aryl group.

Herein, examples of the arylcarbonyl group having 6 to 30 ring carbonatoms include a phenyl carbonyl group, diphenyl carbonyl group, naphthylcarbonyl group, and triphenyl carbonyl group.

Herein, the alkylthio group having 1 to 30 carbon atoms, the alkylthiogroup having 1 to 50 carbon atoms, the arylthio group having 6 to 30ring carbon atoms, and the arylthio group having 6 to 50 ring carbonatoms are each represented by —SR_(V). Examples of R_(V) include theabove alkyl group having 1 to 30 carbon atoms, the above alkyl grouphaving 1 to 50 carbon atoms, the above aryl group having 6 to 30 ringcarbon atoms, and the above aryl group having 6 to 50 ring carbon atoms.The alkylthio group preferably has 1 to 20 carbon atoms. The arylthiogroup preferably has 6 to 20 ring carbon atoms.

Herein, examples of the halogen atom include a fluorine atom, a chlorineatom, a bromine atom and an iodine atom, among which a fluorine atom ispreferable.

Herein, “carbon atoms forming a ring (ring carbon atoms)” mean carbonatoms forming a saturated ring, unsaturated ring, or aromatic ring.“Atoms forming a ring (ring atoms)” mean carbon atoms and hetero atomsforming a ring including a saturated ring, unsaturated ring, or aromaticring.

Herein, a hydrogen atom includes isotope having different numbers ofneutrons, specifically, protium, deuterium and tritium.

Herein, the substituent meant by “substituted or unsubstituted” is atleast one group selected from the group consisting of an alkynyl grouphaving 2 to 30 carbon atoms, cyano group, hydroxyl group, nitro group,and carboxy group in addition to an aryl group having 6 to 30 ringcarbon atoms, heteroaryl group having to 30 ring atoms, alkyl group(linear or branched alkyl group) having 1 to 30 carbon atoms, cycloalkylgroup having 3 to 30 ring carbon atoms, alkyl halide group having 1 to30 carbon atoms, alkylsilyl group having 3 to 30 carbon atoms, arylsilylgroup having 6 to 30 ring carbon atoms, alkoxy group having 1 to 30carbon atoms, aryloxy group having 6 to 30 carbon atoms, substitutedamino group, alkylthio group having 1 to 30 carbon atoms, arylthio grouphaving 6 to 30 ring carbon atoms, aralkyl group having 7 to 30 carbonatoms, alkenyl group having 2 to 30 carbon atoms, and halogen atom.

Herein, the substituent meant by “substituted or unsubstituted” ispreferably at least one group selected from the group consisting of anaryl group having 6 to ring carbon atoms, heteroaryl group having 5 to30 ring atoms, alkyl group (linear or branched alkyl group) having 1 to30 carbon atoms, halogen atom, and cyano group, further preferably thespecific preferable examples described in each of the substituents.

Herein, the substituent meant by “substituted or unsubstituted” may befurther substituted by at least one group selected from the groupconsisting of an aryl group having 6 to 30 ring carbon atoms, heteroarylgroup having 5 to 30 ring atoms, alkyl group (linear or branched alkylgroup) having 1 to 30 carbon atoms, cycloalkyl group having 3 to 30 ringcarbon atoms, alkyl halide group having 1 to 30 carbon atoms, alkylsilylgroup having 3 to 30 carbon atoms, arylsilyl group having 6 to 30 ringcarbon atoms, alkoxy group having 1 to 30 carbon atoms, aryloxy grouphaving 6 to 30 carbon atoms, substituted amino group, alkylthio grouphaving 1 to carbon atoms, arylthio group having 6 to 30 ring carbonatoms, aralkyl group having 7 to 30 carbon atoms, alkenyl group having 2to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms,halogen atom. cyano group, hydroxyl group, nitro group, and carboxygroup. In addition, a plurality of ones of the substituent may bemutually bonded to form a ring.

Herein, the substituent further substituting for the substituent meantby “substituted or unsubstituted” is preferably at least one groupselected from the group consisting of an aryl group having 6 to 30 ringcarbon atoms, heteroaryl group having 5 to 30 ring atoms, alkyl group(linear or branched alkyl group) having 1 to 30 carbon atoms, halogenatom, and cyano group, and is further preferably at least one groupselected from the specific preferable examples described in each of thesubstituents.

“Unsubstituted” in “substituted or unsubstituted” means that a group isnot substituted by the above-described substituents but bonded with ahydrogen atom.

Herein, “XX to YY carbon atoms” in the description of “substituted orunsubstituted ZZ group having XX to YY carbon atoms” represent carbonatoms of an unsubstituted ZZ group and do not include carbon atoms of asubstituent(s) of the substituted ZZ group. Herein, “YY” is larger than“XX.” “XX” and “YY” each mean an integer of 1 or more.

Herein, “XX to YY atoms” in the description of “substituted orunsubstituted ZZ group having XX to YY atoms” represent atoms of anunsubstituted ZZ group and does not include atoms of a substituent(s) ofthe substituted ZZ group. Herein, “YY” is larger than “XX.” “XX” and“YY” each mean an integer of 1 or more.

The same description as the above applies to “substituted orunsubstituted” in compounds or partial structures thereof describedherein.

Herein, when the substituents are bonded to each other to form a ring,the ring is structured to be a saturated ring, an unsaturated ring, anaromatic hydrocarbon ring or a hetero ring.

Herein, examples of the aromatic hydrocarbon group and the heterocyclicgroup in the linking group include a divalent or multivalent groupobtained by eliminating one or more atoms from the above monovalentgroups.

The organic EL device according to the exemplary embodiment emits lightat a high efficiency.

Moreover, the organic EL device according to the exemplary embodimentcan improve the luminous efficiency of the organic EL deviceparticularly in the blue wavelength region.

Electronic Device

The organic EL device 1 according to the exemplary embodiments isapplicable to an electronic device such as a display device and alight-emitting device. Examples of the display device include a displaycomponent (e.g., en organic EL panel module), TV, mobile phone, tabletand personal computer. Examples of the light-emitting device include anilluminator and a vehicle light.

Second Exemplary Embodiment

An arrangement of an organic EL device according to a second exemplaryembodiment will be described. In the description of the second exemplaryembodiment, the same components as those in the first exemplaryembodiment are denoted by the same reference signs and names to simplifyor omit an explanation of the components. In the second exemplaryembodiment, any materials and compounds that are not specified may bethe same as those in the first exemplary embodiment.

The organic EL device according to the second exemplary embodiment isdifferent from the organic EL device according to the first exemplaryembodiment in that the emitting layer further includes a third compound.The rest of the arrangement of the organic EL device according to thesecond exemplary embodiment is the same as as in the first exemplaryembodiment.

Third Compound

It is preferable that a singlet energy S₁(M3) of the third compound anda singlet energy S₁(M1) of the first compound satisfy a relationship ofNumerical Formula 2 below.S ₁(M3)>S ₁(M1)  (Numerical Formula 2).

The third compound may be a delayed fluorescent compound or a compoundexhibiting no delayed fluorescence.

The third compound is also preferably a host material (occasionallyreferred to as a matrix material). When the first compound and the thirdcompound are the host materials, for instance, one of the compounds maybe referred to as a first host material and the other may be referred toas a second host material.

Although the third compound is not particularly limited, the thirdcompound is preferably a compound other than an amine compound.Moreover, the third compound may be a carbazole derivative, dibenzofuranderivative, dibenzothiophene derivative, however, the third compound isnot limited thereto.

It is also preferable that the third compound has at least one of apartial structure represented by a formula (31) and a partial structurerepresented by a formula (32) in one molecule.

In the formula (31), Y₃₁ to Y₃₆ each independently represent a nitrogenatom or a carbon atom bonded to another atom in the molecule of thethird compound.

At least one of Y₃₁ to Y₃₆ is a carbon atom bonded to another atom inthe molecule of the third compound.

In the formula (32), Y₄₁ to Y₄₈ each independently represent a nitrogenatom or a carbon atom bonded to another atom in the molecule of thethird compound.

At least one of Y₄₁ to Y₄₈ is a carbon atom bonded to another atom inthe molecule of the third compound.

X₃₀ represents a nitrogen atom, an oxygen atom or a sulfur atom.

In the formula (32), it is also preferable that at least two of Y₄₁ toY₄₈ are carbon atoms bonded to other atoms in the molecule of the thirdcompound to form a cyclic structure including the carbon atoms.

For instance, the partial structure represented by the formula (32) ispreferably any one selected from the group consisting of partialstructures represented by formulae (321), (322), (323), (324), (325) and(326).

In the formulae (321) to (326), X₃₀ each independently represents anitrogen atom, an oxygen atom, or a sulfur atom.

Y₄₁ to Y₄₈ each independently represent a nitrogen atom or a carbon atombonded to another atom in the molecule of the third compound.

X₃₁ each independently represents a nitrogen atom, an oxygen atom, asulfur atom, or a carbon atom.

Y₆₁ to Y₆₄ each independently represent a nitrogen atom or a carbon atombonded to another atom in the molecule of the third compound.

In the exemplary embodiments, the third compound preferably has thepartial structure represented by the formula (323) among thoserepresented by the formulae (321) to (326).

The partial structure represented by the formula (31) is preferablyincluded in the third compound as at least one group selected from thegroup consisting of a group represented by a formula (33) and a grouprepresented by a formula (34).

It is also preferable that the third compound has at least one of thepartial structures represented by the formulae (33) and (34). Sincebonding positions are situated in meta positions as shown in the partialstructures represented by the formulae (33) and (34), an energy gapT_(77K)(M3) at 77 [K] of the third compound can be kept high.

In the formula (33), Y₃₁, Y₃₂, Y₃₄ and Y₃₆ each independently representa nitrogen atom or CR₃₁.

In the formula (34), Y₃₂, Y₃₄ and Y₃₆ each independently represent anitrogen atom or CR₃₁.

In the formulae (33) and (34), R₃₁ each independently represents ahydrogen atom or a substituent.

R₃₁ as the substituent is each independently selected from the groupconsisting of a substituted or unsubstituted aryl group having 6 to 30ring carbon atoms, a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring atoms, a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkylgroup having 1 to 30 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 30 ring carbon atoms, a substituted orunsubstituted aralkyl group having 7 to 30 carbon atoms, a substitutedor unsubstituted silyl group, a substituted germanium group, asubstituted phosphine oxide group, a halogen atom, a cyano group, anitro group, and a substituted or unsubstituted carboxy group.

The substituted or unsubstituted aryl group having 6 to 30 ring carbonatoms in R₃₁ is preferably a non-fused ring.

Wavy lines in the formulae (33) and (34) each show a bonding positionwith another atom or another structure in the molecule of the thirdcompound.

In the formula (33), Y₃₁, Y₃₂, Y₃₄ and Y₃₆ are each independentlypreferably CR₃₁, in which a plurality of R₃₁ are the same or different.

In the formula (34), Y₃₂, Y₃₄ and Y₃₆ are each independently preferablyCR₃₁, in which a plurality of R₃₁ are the same or different.

The substituted germanium group is preferably represented by —Ge(R₃₀₁)₃.R₃₀₁ is each independently a substituent. The substituent R₃₀₁ ispreferably a substituted or unsubstituted alkyl group having 1 to 30carbon atoms or a substituted or unsubstituted aryl group having 6 to 30ring carbon atoms. A plurality of R₃₀₁ are mutually the same ordifferent.

The partial structure represented by the formula (32) is preferablyincluded in the third compound as at least one group selected from thegroup consisting of groups represented by formulae (35) to (39) and agroup represented by a formula (30a).

In the formula (35), Y₄₁ to Y₄₈ each independently represent a nitrogenatom or CR₃₂.

In the formulae (36) and (37), Y₄₁ to Y₄₅, Y₄₇ and Y₄₈ eachindependently represent a nitrogen atom or CR₃₂.

In the formula (38), Y₄₁, Y₄₂, Y₄₄, Y₄₅, Y₄₇, and Y₄₈ each independentlyrepresent a nitrogen atom or CR₃₂.

In the formula (39), Y₄₂ to Y₄₈ each independently represent a nitrogenatom or CR₃₂.

In the formula (30a), Y₄₂ to Y₄₈ each independently represent a nitrogenatom or CR₃₂.

In the formulae (35) to (39) and (30a), R₃₂ each independentlyrepresents a hydrogen atom or a substituent.

R₃₂ as the substituent is selected from the group consisting of asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1to 30 carbon atoms, a substituted or unsubstituted cycloalkyl grouphaving 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkylgroup having 7 to 30 carbon atoms, a substituted or unsubstituted silylgroup, a substituted germanium group, a substituted phosphine oxidegroup, a halogen atom, a cyano group, a nitro group, and a substitutedor unsubstituted carboxy group.

A plurality of R₃₂ are mutually the same or different.

In the formulae (35) and (36), X₃₀ represents a nitrogen atom.

In the formulae (37) to (39) and (30a), X₃₀ represents NR₃₃, an oxygenatom or a sulfur atom.

R₃₃ is selected from the group consisting of a substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms, a substitutedor unsubstituted heteroaryl group having 5 to 30 ring atoms, asubstituted or unsubstituted alkyl group having 1 to 30 carbon atoms, asubstituted or unsubstituted fluoroalkyl group having 1 to 30 carbonatoms, a substituted or unsubstituted cycloalkyl group having 3 to 30ring carbon atoms, a substituted or unsubstituted aralkyl group having 7to carbon atoms, a substituted or unsubstituted silyl group, asubstituted germanium group, a substituted phosphine oxide group, afluorine atom, a cyano group, a nitro group, and a substituted orunsubstituted carboxy group.

A plurality of R₃₃ are mutually the same or different.

The substituted or unsubstituted aryl group having 6 to 30 ring carbonatoms in R₃₃ is preferably a non-fused ring.

Wavy lines in the formulae (35) to (39) and (30a) each show a bondingposition with another atom or another structure in the molecule of thethird compound.

In the formula (35), Y₄₁ to Y₄₈ are preferably each independently CR₃₂.In the formulae (36) and (37), Y₄₁ to Y₄₅, Y₄₇ and Y₄₈ are preferablyeach independently CR₃₂.

In the formula (38), Y₄₁, Y₄₂, Y₄₄, Y₄₅, Y₄₇ and Y₄₈ are preferably eachindependently CR₃₂.

In the formula (39), Y₄₂ to Y₄₈ are preferably each independently CR₃₂.

In the formula (30a), Y₄₂ to Y₄₇ are preferably each independently CR₃₂.

A plurality of R₃₂ are mutually the same or different.

In the third compound, X₃₀ is preferably an oxygen atom or a sulfuratom, more preferably an oxygen atom.

In the third compound, R₃₁ and R₃₂ each independently represent ahydrogen atom or a substituent. R₃₁ and R₃₂ as the substituents arepreferably each independently a group selected from the group consistingof a fluorine atom, a cyano group, a substituted or unsubstituted alkylgroup having 1 to 30 carbon atoms, a substituted or unsubstituted arylgroup having 6 to 30 ring carbon atoms, and a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms. R₃₁ and R₃₂are more preferably a hydrogen atom, a cyano group, a substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms, or asubstituted or unsubstituted heteroaryl group having 5 to 30 ring atoms.When R₃₁ and R₃₂ as the substituents are each a substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms, the arylgroup is preferably a non-fused ring.

It is also preferable that the third compound is an aromatic hydrocarboncompound or an aromatic heterocyclic compound. Moreover, it ispreferable that the third compound does not have a fused aromatichydrocarbon ring in a molecule.

Method of Manufacturing Third Compound

The third compound can be manufactured by methods disclosed inInternational Publication No. WO2012/153780, International PublicationNo. WO2013/038650, and the like. Furthermore, the third compound can bemanufactured, for instance, by application of known substitutionreactions and/or materials depending on a target compound.

Examples of the substituent in the third compound are shown below, butthe substituent according to the invention is not limited to theexamples.

Specific examples of the aryl group (occasionally referred to as anaromatic hydrocarbonl group) include a phenyl group, tolyl group, xylylgroup, naphthyl group, phenanthryl group, pyrenyl group, chrysenylgroup, benzo[c]phenanthryl group, benzo[g]chrysenyl group, benzoanthrylgroup, triphenylenyl group, fluorenyl group, 9,9-dimethylfluorenylgroup, benzofluorenyl group, dibenzofluorenyl group, biphenyl group,terphenyl group, quarterphenyl group and fluoranthenyl group, amongwhich a phenyl group, biphenyl group, terphenyl group, quarterphenylgroup, naphthyl group, triphenylenyl group and fluorenyl group may bepreferable.

Specific examples of the aryl group having a substituent include a tolylgroup, xylyl group and 9,9-dimethylfluorenyl group.

As is understood from the specific examples, the aryl group includesboth fused aryl group and non-fused aryl group.

Preferable examples of the aryl group include a phenyl group, biphenylgroup, terphenyl group, quarterphenyl group, naphthyl group,triphenylenyl group and fluorenyl group.

Specific examples of the heteroaryl group (occasionally referred to as aheterocyclic group, heteroaromatic ring group or aromatic heterocyclicgroup) include a pyrrolyl group, pyrazolyl group, pyrazinyl group,pyrimidinyl group, pyridazynyl group, pyridyl group, triazinyl group,indolyl group, isoindolyl group, imidazolyl group, benzimidazolyl group,indazolyl group, imidazo[1,2-a]pyridinyl group, furyl group,benzofuranyl group, isobenzofuranyl group, dibenzofuranyl group,azadibenzofuranyl group, thiophenyl group, benzothiophenyl group,dibenzothiophenyl group, azadibenzothiophenyl group, quinolyl group,isoquinolyl group, quinoxalinyl group, quinazolinyl group,naphthyridinyl group, carbazolyl group, azacarbazolyl group,phenanthridinyl group, acridinyl group, phenanthrolinyl group,phenazinyl group, phenothiazinyl group, phenoxazinyl group, oxazolylgroup, oxadiazolyl group, furazanyl group, benzoxazolyl group, thienylgroup, thiazolyl group, thiadiazolyl group, benzothiazolyl group,triazolyl group and tetrazolyl group, among which a dibenzofuranylgroup, dibenzothiophenyl group, carbazolyl group, pyridyl group,pyrimidinyl group, triazinyl group, azadibenzofuranyl group andazadibenzothiophenyl group may be preferable.

The heteroaryl group is preferably a dibenzofuranyl group,dibenzothiophenyl group, carbazolyl group, pyridyl group, pyrimidinylgroup, triazinyl group, azadibenzofuranyl group or azadibenzothiophenylgroup, and further preferably a dibenzofuranyl group, dibenzothiophenylgroup, azadibenzofuranyl group and azadibenzothiophenyl group.

In the third compound, it is also preferable that the substituted silylgroup is selected from the group consisting of a substituted orunsubstituted trialkylsilyl group, a substituted or unsubstitutedarylalkylsilyl group, or a substituted or unsubstituted triarylsilylgroup.

Specific examples of the substituted or unsubstituted trialkylsilylgroup include trimethylsilyl group and triethylsilyl group.

Specific examples of the substituted or unsubstituted arylalkylsilylgroup include diphenylmethylsilyl group, ditolylmethylsilyl group, andphenyldimethylsilyl group.

Specific examples of the substituted or unsubstituted triarylsilyl groupinclude triphenylsilyl group and tritolylsilyl group.

In the third compound, it is also preferable that the substitutedphosphine oxide group is a substituted or unsubstituted diaryl phosphineoxide group.

Specific examples of the substituted or unsubstituted diaryl phosphineoxide group include a diphenyl phosphine oxide group and ditolylphosphine oxide group.

In the third compound, examples of the substituted carboxy group includebenzoyloxy group.

Relationship Between First Compound, Second Compound and Third Compoundin Emitting Layer

The first compound, the second compound, and the third compound in theemitting layer preferably satisfy the relationship of Numerical Formula1 and the relationship of Numerical Formula 2. In other words, arelationship of the following numerical formula (Numerical Formula 3) ispreferably satisfied.S ₁(M3)>S ₁(M1)>S ₁(M2)  (Numerical Formula 3).

An energy gap T_(77K)(M3) at 77 [K] of the third compound is preferablylarger than the energy gap T_(77K)(M1) at 77 [K] of the first compound.In other words, a relationship of the following numerical formula(Numerical Formula 5) is preferably satisfied.T _(77K)(M3)>T _(77K)(M1)  (Numerical Formula 5).

The energy gap T_(77K)(M3) at 77 [K] of the third compound is preferablylarger than the energy gap T_(77K)(M2) at 77 [K] of the second compound.In other words, a relationship of the following numerical formula(Numerical Formula 6) is preferably satisfied.T _(77K)(M3)>T _(77K)(M2)  (Numerical Formula 6).

The first compound, the second compound, and the third compound in theemitting layer preferably satisfy the relationship of Numerical Formula4 and the relationship of Numerical Formula 5. In other words, arelationship of the following numerical formula (Numerical Formula 7) ispreferably satisfied.T _(77K)(M3)>T _(77K)(M1)>T _(77K)(M2)  (Numerical Formula 7).

When the organic EL device of the exemplary embodiment emits light, itis preferable that the second compound in the emitting layer mainlyemits light.

Content Ratio of Compounds in Emitting Layer

Content ratios of the respective first, second and third compounds inthe emitting layer preferably range as follows.

The content ratio of the first compound preferably ranges from 10 mass %to 80 mass %, more preferably from 10 mass % to 60 mass %, furtherpreferably from mass % to 60 mass %.

The content ratio of the second compound preferably ranges from 0.01mass % to 10 mass %, more preferably from 0.01 mass % to 5 mass %,further preferably from 0.01 mass % to 1 mass %.

The content ratio of the third compound preferably ranges from 10 mass %to 80 mass %.

An upper limit of the total of the respective content ratios of thefirst, second and third compounds in the emitting layer is 100 mass %.It should be noted that the emitting layer of the exemplary embodimentmay further contain another material in addition to the first, secondand third compounds.

FIG. 5 shows an example of a relationship among energy levels of thefirst compound, the second compound and the third compound in theemitting layer. In FIG. 5, S0 represents a ground state. S1(M1)represents the lowest singlet state of the first compound.

T1(M1) represents the lowest triplet state of the first compound. S1(M2)represents the lowest singlet state of the second compound.

T1(M2) represents the lowest triplet state of the second compound.S1(M3) represents the lowest singlet state of the third compound.

T1(M3) represents the lowest triplet state of the third compound. Adashed arrow directed from S1(M1) to S1(M2) in FIG. 5 represents Forsterenergy transfer from the lowest singlet state of the first compound tothe lowest singlet state of the second compound.

As shown in FIG. 5, when a compound having a small ΔST(M1) is used asthe first compound, inverse intersystem crossing from the lowest tripletstate T1(M1) to the lowest singlet state S1(M1) can be caused by a heatenergy. Subsequently, Förster energy transfer from the lowest singletstate S1(M1) of the first compound the second compound occurs togenerate the lowest singlet state S1(M2). Consequently, fluorescencefrom the lowest singlet state S1(M2) of the second compound can beobserved. It is inferred that the internal quantum efficiency can betheoretically raised up to 100% also by using delayed fluorescence bythe TADF mechanism.

The organic EL device according to the second exemplary embodiment emitslight at a high efficiency.

Moreover, the organic EL device according to the second exemplaryembodiment can improve the luminous efficiency of the organic EL deviceparticularly in the blue wavelength region.

The organic EL device of the second exemplary embodiment, in which theemitting layer includes the delayed fluorescent first compound, thefluorescent second compound, and the third compound having the singletenergy larger than that of the first compound, improves the luminousefficiency. It is presumed that an improvement in the luminousefficiency is caused by an improvement in a carrier balance of theemitting layer since the emitting layer contains the third compound.

The organic EL device according to the second exemplary embodiment isapplicable to an electronic device such as a display device and alight-emitting device in the same manner as the organic EL deviceaccording to the first exemplary embodiment.

Modification of Exemplary Embodiments

It should be noted that the invention is not limited to the aboveexemplary embodiments but may include any modification and improvementas long as such modification and improvement are compatible with theinvention.

For instance, the emitting layer is not limited to a single layer, butis multi-layered emitting layers in some embodiments. When the organicEL device has a plurality of emitting layers, it is only required thatat least one of the emitting layers satisfies the conditions describedin the above exemplary embodiments. For instance, in some embodiments,the rest of the emitting layers is a fluorescent emitting layer or aphosphorescent emitting layer using emission by electronic transitionfrom the triplet state directly to the ground state.

Moreover, when the organic EL device has the plurality of emittinglayers, in some embodiments, the plurality of emitting layers areadjacent to each other, or provide a so-called tandem-type organic ELdevice in which a plurality of emitting units are layered through anintermediate layer.

Moreover, for instance, in some embodiments, a blocking layer isadjacent to at least one side of the emitting layer among a side closeto the anode and a side close to the cathode. The blocking layer ispreferably provided in contact with the emitting layer to block at leastone of holes, electrons and excitons.

For instance, when the blocking layer is provided in contact with theside close to the cathode of the emitting layer, the blocking layerpermits transport of electrons, but blocks holes from reaching a layerprovided close to the cathode (e.g., the electron transporting layer)beyond the blocking layer. When the organic EL device includes anelectron transporting layer, the blocking layer is preferably interposedbetween the emitting layer and the electron transporting layer.

When the blocking layer is provided in contact with the side close tothe anode of the emitting layer, the blocking layer permits transport ofholes, but blocks electrons from reaching a layer provided close to theanode (e.g., the hole transporting layer) beyond the blocking layer.When the organic EL device includes the hole transporting layer, theblocking layer is preferably interposed between the emitting layer andthe hole transporting layer.

Further, the blocking layer may be provided in contact with the emittinglayer to prevent an excitation energy from leaking from the emittinglayer into neighboring layers. The blocking layer blocks excitonsgenerated in the emitting layer from moving into a layer provided closeto the electrode (e.g., the electron transporting layer and the holetransporting layer) beyond the blocking layer.

The emitting layer is preferably bonded to the blocking layer.

Specific structure and shape of the components for implementing theinvention may be designed in any manner as long as the object of theinvention can be achieved.

EXAMPLES

Examples of the invention will be described below. However, theinvention is by no means limited to Examples.

Compounds

Compounds used for manufacturing the organic EL device will be shownbelow.

Synthesis of Compound(s)

Synthesis Example 1: Synthesis of Compound BD-1

(1-1) Synthesis of Intermediate (Int-1)

To a three-necked flask, 2.0 g (3.29 mmol) of a starting material (SM-1:isomer mixture), 0.59 g (3.95 mmol) of 2-formylphenyl boronic acid, 0.87g (8.23 mmol) of sodium carbonate, 10 mL of 1,2-dimethoxyethane (DME),and 10 mL of water were added. Subsequently, 0.19 g (0.17 mmol) oftetrakis(triphenylphosphine)palladium was further added to the flask toprovide a mixture solution. The mixture solution was heated for refluxwith stirring for eight hours under an argon gas atmosphere. After themixture solution was heated for reflux with stirring, an organic layerwas separated from the mixture solution. The separated organic layer wascondensed under reduced pressure. The obtained residue was refined bysilica-gel column chromatography. A mixture solvent of dichloromethaneand n-hexane was used as an eluent. After the refinement, the obtainedsolid was suspended in and washed with methanol to obtain anintermediate (Int-1). A yield of the intermediate (Int-1) was 2.1 g anda yield rate thereof was 100%.

(1-2) Synthesis of Intermediate (Int-2)

To a three-necked flask, 1.7 g (4.98 mmol) of (methoxymethyl)triphenylphosphonium chloride and 3.5 mL of tetrahydrofuran (THF) were added.Subsequently, 0.61 g (5.48 mmol) of potassium t-butoxide was added tothe flask to prepare a ylide solution in red. Further, a THE solution (5mL) of the intermediate (Int-1) (2.1 g (3.29 mmol)) was added to theflask and stirred for two hours under argon atmosphere. After water wasadded to the flask to stop a reaction, dichloromethane was used forextraction. The extracted organic layer was condensed under reducedpressure. The obtained residue was refined by silica-gel columnchromatography. A mixture solvent of dichloromethane and n-hexane wasused as an eluent. After the refinement, the obtained solid wassuspended in and washed with methanol to obtain an intermediate (Int-2).A yield of the intermediate (Int-2) was 1.8 g and a yield rate thereofwas 82%.

(1-3) Synthesis of Compound BD-1

To a three-necked flask, 1.8 g (2.72 mmol) of the intermediate (Int-2)and 25 mL of dichloromethane were added. Subsequently, 0.26 g (2.72mmol) of methane sulfonic acid was dropped in the flask and was stirredfor 0.5 hour. After sodium hydrogen carbonate aqueous solution was addedto the flask to stop a reaction, dichloromethane was used forextraction. The extracted organic layer was condensed under reducedpressure. The obtained residue was refined by silica-gel columnchromatography. A mixture solvent of dichloromethane and n-hexane wasused as an eluent. After the refinement, the obtained solid wassuspended in and washed with methanol to obtain a target substance(compound BD-1) in a form of a yellow solid. A yield of the compound was0.84 g and a yield rate thereof was 49%. A result of FD-MS (FieldDesorption Mass Spectrometry) analysis showed m/e=628 relative to amolecular weight of 628. It should be noted that BD-1 was a mixture ofBD-1a and BD-1b, which was derived from that the starting material(SM-1) was the isomer mixture (mixture of SM-1a and SM-1b). In areaction formula of Synthesis Example 1, a representative structure of“SM-1” was shown only by a structure of SM-1a and a representativestructure of “BD-1” was shown only by a structure of BD-1a. Structuresof the intermediates Int-1 and Int-2 were also shown only by theintermediate obtained from SM-1a.

Synthesis Example 2: Synthesis of Compound BD-2

(2-1) Synthesis of Intermediate 2A

To a three-necked flask, under argon atmosphere, 3.0 g (4.94 mmol) ofthe starting material (SM-1: isomer mixture), 2.5 g (9.88 mmol) of2-nitrophenyl boronic acid pinacol ester, and 30 mL of1,2-dimethoxyethane (DME) were added. Subsequently, 0.16 g (0.2 mmol) ofPdCl₂(dppf)/CH₂Cl₂ was added to the flask and then 7.4 mL of an aqueoussolution of 2M sodium carbonate was added thereto. The obtained mixturesolution was heated with stirring at 80 degrees C. for six hours. Afterheated with stirring, the mixture solution was returned to a roomtemperature and a deposited solid was filtrated. After the obtainedsolid was dissolved in toluene, added with silica gel and stirred, theobtained solution was filtrated and condensed to obtain an intermediate2A. A yield of the intermediate 2A was 2.74 g and a yield rate thereofwas 85%.

(2-2) Synthesis of Intermediate 2B

To a three-necked flask, 2.1 g (3.23 mmol) of the intermediate 2A, 2.12g (8.08 mmol) of triphenylphosphine (PPh₃), and 20 mL of orthodichlorobenzene (o-DCB) were added, and heated with stirring at 140degrees C. for 24 hours under argon atmosphere. During the reaction,2.11 g of triphenylphosphine was additionally put in the flask. Afterthe solvent was distilled away under reduced pressure, the obtainedresidue was refined by silica-gel column chromatography (a mobile phase;hexane:toluene=2:1 (volume ratio)), so that an intermediate 2B wasobtained. A yield of the intermediate 2B was 1.59 g and a yield ratethereof was 75%.

(2-3) Synthesis of Compound BD-2

To a three-necked flask, under argon atmosphere, 1.57 g (2.54 mmol) ofthe intermediate 2B, 0.6 g (3.81 mmol) of bromobenzene, 47 mg (0.051mmol) of Pd₂(dba)₃, 0.13 g (0.20 mmol) of t-Bu₃P—HBF₄, and 0.34 g (3.56mmol) of t-BuONa were added and subsequently 20 mL of toluene was added.The obtained mixture solution was heated with stirring at 105 degrees C.for seven hours. After heated with stirring, the mixture solution wasreturned to the room temperature and a deposited solid was filtrated.After the obtained solid was dissolved in chlorobenzene, added withsilica gel and stirred, the obtained solution was filtrated andcondensed. The obtained residue was refined by silica-gel columnchromatography (a mobile phase; hexane:toluene=2:1 (volume ratio)).Further, the obtained solid was suspended in and washed with ethylacetate to obtain a compound BD-2. A yield of the compound was 0.78 gand a yield rate thereof was 44%. A result of FD-MS analysis showedm/e=693 relative to a molecular weight of 693. It should be noted thatBD-2 was a mixture of BD-2a and BD-2b, which was derived from that thestarting material (SM-1) was the isomer mixture (mixture of SM-1a andSM-1b) In a reaction formula of Synthetic Example 2, the representativestructure of “SM-1” was shown only by the structure of SM-1a and arepresentative structure of “BD-2” was shown only by a structure ofBD-2a. Both structures of the intermediate 2A and the intermediate 2Bwere shown only by a structure of an intermediate obtained from SM-1a.

Synthesis Example 3: Synthesis of Compound BD-3

To a three-necked flask, under argon atmosphere, 2.33 g (3.77 mmol) ofthe intermediate 2B, 1.37 g (7.53 mmol) of 4-bromobenzonitrile, 0.14 g(0.15 mmol) of Pd₂(dba)₃, 0.29 g (0.61 mmol) of XPhos, and 0.51 g (5.27mmol) of t-BuONa were added and subsequently 20 mL of toluene was added.The obtained mixture solution was heated with stirring at 100 degrees C.for 15 hours. After heated with stirring, the mixture solution wasreturned to the room temperature and a deposited solid was filtrated.After the obtained solid was dissolved in chlorobenzene, added withsilica gel and stirred, the obtained solution was filtrated andcondensed. The obtained solid was suspended in and washed with methanolto obtain a compound BD-3. A yield of the compound was 2.19 g and ayield rate thereof was 81%. A result of FD-MS analysis showed thatm/e=718 relative to a molecular weight of 718. It should be noted thatBD-3 was a mixture of BD-3a and BD-3b, which was derived from that thestarting material (SM-1) was the isomer mixture (mixture of SM-1a andSM-1b). In a reaction formula of Synthetic Example 3, a representativestructure of “BD-3” was shown only by a structure of BD-3a. Therepresentative structure of the intermediate 2B was also shown only bythe structure of the intermediate obtained from SM-1a.

Synthesis Example 4: Synthesis of Compound BD-4

(4-1) Synthesis of Intermediate 4A

To a three-necked flask, 41.5 g (189 mmol) of5-bromo-2-chlorobenzaldehyde, 39.0 g (227 mmol) ofnaphthalene-2-ylboronic acid, 189 mL (378 mmol) of 2M sodium carbonateaqueous solution, and 378 mL of 1,2-dimethoxyethane (DME) were added.Subsequently, 4.37 g (3.78 mmol) oftetrakis(triphenylphosphine)palladium was further added to the flask toprovide a mixture solution. The mixture solution was heated for refluxwith stirring for eight hours under an argon gas atmosphere. After themixture solution was heated for reflux with stirring, an organic layerwas separated with toluene. The separated organic layer was condensedunder reduced pressure. The obtained residue was suspended in and washedwith methanol to obtain an intermediate 4A. A yield of the intermediatewas 49.4 g and a yield rate thereof was 98%.

(4-2) Synthesis of Intermediate 4B

To a three-necked flask, under argon atmosphere, 30.0 g (112 mmol) ofthe intermediate 4A, 34.3 g (135 mmol) of bis(pinacolato)diboron, 2.06 g(2.25 mmol) of Pd₂(dba)₃, 4.29 g (9.00 mmol) of XPhos, and 22.1 g (225mmol) of potassium acetate were added and subsequently 375 mL of1,4-dioxane was added. The obtained mixture solution was heated withstirring at 80 degrees C. for four hours. After the mixture solution wasreturned to the room temperature, water was added to the three-neckedflask and an organic layer was extracted with ethyl acetate. After thesolvent was distilled away from the extracted organic layer underreduced pressure, the obtained residue was refined by silica-gel columnchromatography (a mobile phase; hexane:dichloromethane), so that anintermediate 4B was obtained. A yield of the intermediate was 40.3 g anda yield rate thereof was 100%.

(4-3) Synthesis of Intermediate 4C

To a three-necked flask, under argon atmosphere, 5.0 g (8.23 mmol) ofthe starting material (SM-1: isomer mixture), 4.42 g (12.3 mmol) of theintermediate 4B, and 82 mL of toluene were added. Subsequently, 0.13 g(0.16 mmol) of PdCl₂(dppf)/CH₂Cl₂ was added to the flask and then 8.2 mLof 2M sodium carbonate aqueous solution was added thereto. The obtainedmixture solution was heated with stirring at 90 degrees C. for 22 hours.After heated with stirring, the mixture solution was returned to theroom temperature. An aqueous layer was removed from the mixturesolution. An organic layer was added with silica gel and stirred.Subsequently, the obtained solution was filtrated and condensed. Theobtained residue was washed with ethyl acetate and filtrated to obtainan intermediate 4C. A yield of the intermediate was 4.71 g and a yieldrate thereof was 75%.

(4-4) Synthesis of Intermediate 4D

To a three-necked flask, 6.03 g (17.6 mmol) of (methoxymethyl)triphenylphosphonium chloride and 60 mL of tetrahydrofuran (THF) were added.Subsequently, 2.17 g (19.4 mmol) of t-BuOK was added to the flask toprepare a ylide solution in red. Further, a THE solution (60 mL) of theintermediate 4C (8.90 g (11.7 mmol)) was added to the flask and stirredfor two hours under argon atmosphere. After water was added to the flaskto stop a reaction, dichloromethane was used for extraction. Theextracted organic layer was condensed under reduced pressure. Theobtained residue was refined by silica-gel column chromatography. Amixture solvent of dichloromethane and n-hexane was used as an eluent.After the refinement, the obtained solid was suspended in and washedwith methanol to obtain an intermediate 4D. A yield of the intermediatewas 7.98 g and a yield rate thereof was 86%.

(4-5) Synthesis of Compound BD-4

To a three-necked flask, 7.98 g (10.1 mmol) of the intermediate 4D and100 mL of dichloromethane were added. Subsequently, 0.97 g (10.1 mmol)of methane sulfonic acid was dropped in the flask and was stirred for0.5 hour. After sodium hydrogen carbonate aqueous solution was added tothe flask to stop a reaction, dichloromethane was used for extraction.The extracted organic layer was condensed under reduced pressure. Theobtained residue was refined by silica-gel column chromatography. Afterthe refinement, the obtained solid was suspended in and washed withmethanol to obtain a target substance (compound BD-4) in a form of ayellow solid. A yield of the compound was 4.0 g and a yield rate thereofwas 52%. A result of FD-MS (Field Desorption Mass Spectrometry) analysisshowed m/e=754 relative to a molecular weight of 754. It should be notedthat BD-4 was a mixture of BD-4a and BD-4b, which was derived from thatthe starting material (SM-1) was the isomer mixture (mixture of SM-1aand SM-1b). In a reaction formula of Synthetic Example 4, therepresentative structure of “SM-1” was shown only by the structure ofSM-1a and a representative structure of “BD-4” was shown only by astructure of BD-4a. A representative structure of each of theintermediates 4A, 4B, 4C and 4D was also shown only by the structure ofthe intermediate obtained from SM-1a.

Synthesis Example 5: Synthesis of Compound BD-5

A compound BD-5 was obtained in the same manner as in Synthesis Example4 except that 2,6-dimethylphenylboronic acid was used in place ofnaphthalene-2-ylboronic acid used at (4-1) Synthesis of Intermediate 4Ain Synthesis Example 4: Synthesis of Compound BD-4. A result of FD-MS(Field Desorption Mass Spectrometry) analysis showed m/e=732 relative toa molecular weight of 732. It should be noted that BD-5 was a mixture ofBD-5a and BD-5b, which was derived from that the starting material(SM-1) was the isomer mixture (mixture of SM-1a and SM-1b).

Synthesis Example 6: Synthesis of Compound BD-6

(6-1) Synthesis of Intermediate 6A

To a three-necked flask, under argon atmosphere, 5.00 g (8.23 mmol) ofthe starting material (SM-1: isomer mixture), 4.18 g (16.5 mmol) ofbis(pinacolato)diboron, 0.20 g (0.247 mmol) of PdCl₂(dppf)/CH₂Cl₂, and1.62 g (16.5 mmol) of potassium acetate were added and subsequently 50mL of 1,4-dioxane was added. The obtained mixture solution was heatedwith stirring at 100 degrees C. for four hours. After the mixturesolution was returned to the room temperature, the mixture solution wasadded with silica gel, filtrated, and washed with toluene. After thesolvent was distilled away under reduced pressure, the obtained residuewas refined by silica-gel column chromatography (the mobile phase;hexane:toluene), so that an intermediate 6A was obtained. A yield of theintermediate was 3.66 g and a yield rate thereof was 63%.

(6-2) Synthesis of Intermediate 6B

To a three-necked flask, under argon atmosphere, 1.37 g (6.05 mmol) of4-bromo-3-nitrobenzonitrile, 3.60 g (5.50 mmol) of the intermediate 6A,and 40 mL of DME were added, subsequently 0.090 g (0.11 mmol) ofPdCl₂(dppf)/CH₂Cl₂ was added, and subsequently 3.85 mL of 2M sodiumcarbonate aqueous solution was added. The obtained mixture solution washeated with stirring at 80 degrees C. for 14 hours. After the mixturesolution was returned to the room temperature, the mixture solution wasfiltrated and washed with toluene. After the solvent was distilled awayunder reduced pressure, the obtained residue was refined by silica-gelcolumn chromatography (the mobile phase; hexane:toluene), so that anintermediate 6B was obtained. A yield of the intermediate was 1.64 g anda yield rate thereof was 44%.

(6-3) Synthesis of Compound BD-6

A compound BD-6 was obtained in the same manner as in Synthesis Example2 except that the intermediate 6B was used in place of the intermediate2A used at (2-2) Synthesis of Intermediate 2B in Synthesis Example 2:Synthesis of Compound BD-2. A result of FD-MS (Field Desorption MassSpectrometry) analysis showed m/e=718 relative to a molecular weight of718. It should be noted that BD-6 was a mixture of BD-6a and BD-6b,which was derived from that the starting material (SM-1) was the isomermixture (mixture of SM-1a and SM-1b).

Synthesis Example 7: Synthesis of Compound BD-7

(7-1) Synthesis of Intermediate 7A

To a three-necked flask, under argon atmosphere, 3.00 g (4.94 mmol) ofthe starting material (SM-1: isomer mixture), 0.63 g (4.94 mmol) of2-chloroaniline, 0.090 g (0.099 mmol) of Pd₂(dba)₃, 0.12 g (0.395 mmol)of t-Bu₃P—HBF₄, and 0.66 g (0.41 mmol) of t-BuONa were added, andsubsequently 30 mL of toluene was added. The obtained mixture solutionwas heated with stirring at 110 degrees C. for six hours. After themixture solution was returned to the room temperature, the mixturesolution was added with silica gel, filtrated, and washed with toluene.After the solvent was distilled away under reduced pressure, theobtained residue was refined by silica-gel column chromatography (themobile phase; hexane:toluene), so that an intermediate 7A was obtained.A yield of the intermediate was 1.34 g and a yield rate thereof was 97%.

(7-2) Synthesis of Intermediate 7B

To a three-necked flask, under argon atmosphere, 0.30 g (0.46 mmol) ofthe intermediate 7A, 10 mg (0.046 mmol) of palladium acetate, 0.034 mg(0.14 mmol) of PCH₃(t-Bu)₂-HBF₄, and 0.095 g (0.69 mmol) of potassiumcarbonate were added and subsequently 10 mL of dimethylacetamide (DMA)was added. The obtained mixture solution was heated with stirring at 160degrees C. for 11 hours. After the mixture solution was returned to theroom temperature, water was added to the mixture solution. The obtainedmixture solution was subjected to extraction with a mixture solution oftoluene and hexane. After the solvent was distilled away under reducedpressure, the obtained residue was refined by silica-gel columnchromatography (the mobile phase; hexane:toluene), so that anintermediate 7B was obtained. A yield of the intermediate was 0.18 g anda yield rate thereof was 64%.

(7-3) Synthesis of Compound BD-7

To a three-necked flask, under argon atmosphere, 0.18 g (0.29 mmol) ofthe intermediate 7B, 0.091 g (0.58 mmol) of bromobenzene, 5.3 mg (5.8μmol) of Pd₂(dba)₅, 6.8 mg (0.023 mmol) of t-Bu₃P—HBF₄, and 0.039 g(0.41 mmol) of t-BuONa were added and subsequently 30 mL of toluene wasadded. The obtained mixture solution was heated with stirring at 110degrees C. for 15 hours. After the mixture solution was returned to theroom temperature, the mixture solution was added with silica gel,filtrated, and washed with toluene. After the solvent was distilled awayunder reduced pressure, the obtained residue was refined by silica-gelcolumn chromatography (the mobile phase; hexane:toluene), so that atarget substance (a compound BD-7) was obtained in a form of a yellowsolid. A yield of the compound was 0.18 g and a yield rate thereof was86%. A result of FD-MS (Field Desorption Mass Spectrometry) analysisshowed m/e=693 relative to a molecular weight of 693. It should be notedthat BD-7 was a mixture of BD-7a and BD-7b, which was derived from thatthe starting material (SM-1) was the isomer mixture (mixture of SM-1aand SM-1b). In a reaction formula of Synthetic Example 7, therepresentative structure of “SM-1” was shown only by the structure ofSM-1a and a representative structure of “BD-7” was shown only by astructure of BD-7a. A representative structure of each of theintermediates 7A and 7B was also shown only by the structure of theintermediate obtained from SM-1a.

Synthesis Example 8: Synthesis of Compound BD-8

To a three-necked flask, under argon atmosphere, 1.00 g (1.65 mmol) ofthe starting material (SM-1: isomer mixture), 0.46 g (1.65 mmol) of2-(2-bromophenyl)phenylboronic acid, 30 mg (0.033 mmol) of Pd₂(dba)₃, 49mg (0.13 mmol) of tricyclohexylphosphine tetrafluoroborate, and 0.70 g(3.30 mmol) of potassium phosphate were added, and subsequently 15 mL ofdimethylacetamide (DMA) was added. The obtained mixture solution washeated with stirring at 150 degrees C. for three hours. After themixture solution was returned to the room temperature, the mixturesolution was added with silica gel, filtrated, and washed with toluene.After the solvent was distilled away under reduced pressure, theobtained residue was refined by silica-gel column chromatography (themobile phase, hexane:toluene), so that a target substance (a compoundBD-8) was obtained in a form of a yellow solid. A yield of the compoundwas 0.22 g and a yield rate thereof was 20%. A result of FD-MS (FieldDesorption Mass Spectrometry) analysis showed m/e=678 relative to amolecular weight of 678. It should be noted that BD-8 was a mixture ofBD-8a and BD-8b, which was derived from that the starting material(SM-1) was the isomer mixture (mixture of SM-1a and SM-1b). In areaction formula of Synthetic Example 8, the representative structure of“SM-1” was shown only by the structure of SM-1a and a representativestructure of “BD-8” was shown only by a structure of BD-8a.

Synthesis Example 9: Synthesis of Compound TADF-1

(9-1) Synthesis of Intermediate A

To a three-necked flask, 7.0 g (50 mmol) of 2-fluorophenylboronic acid,13.4 g (50 mmol) of 2-chloro-4,6-diphenyltriazine, 62.5 mL of 2M sodiumcarbonate aqueous solution, 100 mL of 1,2-dimethoxyethane (DME) and 100mL of toluene were added. Subsequently, 1.73 g (1.5 mmol) oftetrakis(triphenylphosphine)palladium was further added to the flask.The obtained mixture solution was heated for reflux with stirring foreight hours under an argon gas atmosphere. After the mixture solutionwas heated for reflux with stirring, an organic layer was separated fromthe mixture solution. The separated organic layer was condensed underreduced pressure. The obtained residue was refined by silica-gel columnchromatography. A toluene solvent was used as an eluent solvent. Afterthe refinement, the obtained solid was suspended in and washed withmethanol to obtain an intermediate A in a form of a white solid. A yieldof the intermediate was 11.6 g and a yield rate thereof was 71%.

(9-2) Synthesis of Compound TADF-1

To a three-necked flask, 7.3 g (43.6 mmol) of carbazole, 8.0 g (24.4mmol) of the intermediate A, 7.4 g (53.5 mmol) of potassium carbonate,and 50 mL of N-methyl-2-pyrrolidone (NMP) were added. The obtainedmixture solution was heated with stirring at 150 degrees C. for 20 hoursunder argon atmosphere. After heated with stirring, the obtainedreaction solution was poured into 200 mL of water. The deposited solidwas filtrated. Subsequently, the solid was repeatedly suspended in andwashed with ethanol to obtain a target substance (compound TADF-1) in aform of a white solid. A yield of the compound was 6.3 g and a yieldrate thereof was 54%. A result of FD-MS analysis showed m/e=474 relativeto a molecular weight of 474.

Evaluation of Compounds

A method of measuring characteristics of the compounds is shown below.

Delayed Fluorescence

Delayed fluorescence characteristics were checked by measuring transientphotoluminescence (PL) using a device shown in FIG. 2. A sample wasprepared by co-depositing the compounds TADF-1 and TH-2 on a quartzsubstrate at a ratio of the compound TADF-1 being 12 mass % to form a100-nm-thick thin film. There are two types of emission: Prompt emissionobserved promptly when the excited state is achieved by exciting thecompound TADF-1 with a pulse beam (i.e., a beam emitted from a pulselaser) having a wavelength absorbable by the compound TADF-1, and Delayemission observed not promptly when but after the excited state isachieved. The delayed fluorescence in Examples means that the amount ofDelay emission is 5% or more relative to the amount of Prompt emission.Specifically, provided that the amount of Prompt emission is denoted byX_(P) and the amount of Delay emission is denoted by X_(D), a value ofX_(D)/X_(P) is 0.05 or more.

It was found that the amount of Delay Emission was 5% or more relativeto the amount of Prompt Emission in the compound TADF-1. Specifically,it was found that the value of X_(D)/X_(P) was 0.05 or more in thecompound TADF-1.

It was also found that the value of X_(D)/X_(P) was 0.05 or more in acompound TADF-2.

The amount of Prompt emission and the amount of Delay emission can beobtained according to the method as described in “Nature 492, 234-238,2012.” A device used for calculating the amount of Prompt emission andthe amount of Delay emission is not limited to the device described inFIG. 2 and Cited Literatures.

Singlet Energy S₁

A singlet energy S₁ of each of the compound TADF-1, compound TADF-2,compound A-1, compound BD-1, compound BD-2, compound BD-3, compoundBD-4, compound BD-5, compound BD-6, compound BD-7, and compound BD-8 wasmeasured according to the above-described solution method.

The singlet energy S₁ of the compound TADF-1 was 2.90 eV.

The singlet energy S₁ of the compound TADF-2 was 2.90 eV.

The singlet energy S₁ of the compound A-1 was 3.53 eV.

The singlet energy S₁ of the compound BD-1 was 2.75 eV.

The singlet energy S₁ of the compound BD-2 was 2.64 eV.

The singlet energy S₁ of the compound BD-3 was 2.64 eV.

The singlet energy S₁ of the compound BD-4 was 2.70 eV.

The singlet energy S₁ of the compound BD-5 was 2.74 eV.

The singlet energy S₁ of the compound BD-6 was 2.66 eV.

The singlet energy S₁ of the compound BD-7 was 2.59 eV.

The singlet energy S₁ of the compound BD-8 was 2.74 eV.

A singlet energy of a compound DPEPO is 4.0 eV as described in aliterature (APPLIED PHYSICS LETTERS 101, 093306 (2012)).

Main Peak Wavelength of Compounds

Each of the measurement target compounds was dissolved in toluene at aconcentration ranging from 10⁻⁶ mol/liter to 10⁻⁵ mol/liter to prepare atoluene solution. An emission spectrum of each of the measurement targetcompounds in the respective toluene solutions was measured. A peakwavelength of the emission spectrum exhibiting the maximum luminousintensity was defined as a main peak wavelength.

The main peak wavelength of the compound BD-1 was 448 nm.

The main peak wavelength of the compound BD-2 was 462 nm.

The main peak wavelength of the compound BD-3 was 460 nm.

The main peak wavelength of the compound BD-4 was 457 nm.

The main peak wavelength of the compound BD-5 was 451 nm.

The main peak wavelength of the compound BD-6 was 461 nm.

The main peak wavelength of the compound BD-7 was 475 nm.

The main peak wavelength of the compound BD-8 was 450 nm.

An absorption spectrum was measured. Based on the measurement result ofthe absorption spectrum, a molar absorbance coefficient E and Stokesshift ss were calculated.

Molar Absorbance Coefficient ε

The molar absorbance coefficient ε was calculated by dividing anabsorption intensity of an absorption peak located closest to thelong-wavelength region in the absorption spectrum by a solutionconcentration. A unit of the molar absorbance coefficient ε was definedas L/(mol·cm). The absorption peak located closest to thelong-wavelength region is defined as a peak appearing at a positionclosest to the long-wavelength region among peaks appearing in awavelength range from 350 nm to 500 nm and having an absorptionintensity that is at least one tenth of an absorption intensity of themaximum absorption peak.

Absorption Spectrum

An absorption spectrum was measured according to a method describedbelow.

A 20-μmol/L toluene solution of each of the compounds (measurementtarget) was prepared and put in a quartz cell. An absorption spectrum(ordinate axis: absorption intensity, abscissa axis: wavelength) of eachof the samples was measured at a normal temperature (300K). In Examples,the absorption spectrum was measured using a spectrophotometermanufactured by Hitachi, Ltd. (device name: U3310). It should be notedthat the absorption spectrum measuring device may be different from theabove device.

Stokes Shift ss

The Stokes shift ss was calculated by subtracting the absorption peakwavelength, which was used for calculating the molar absorbancecoefficient of the absorption spectrum, from the main peak wavelength ofthe emission spectrum. A unit of the Stokes shift ss was defined as nm.

Table 2 shows the molar absorbance coefficient, the main peak wavelengthof the emission spectrum, the absorption peak wavelength, and the stokesshift of each of the compounds.

TABLE 2 Molar Absorbance Main Peak Wave- Absorption Com- Coefficientlength of Emission Peak Wave- Stokes Shift pound [L/(mol · cm)] Spectrum[nm] length [nm] [nm] BD-1 69400 448 442 6 BD-2 53500 462 454 8 BD-359600 460 454 6 BD-4 88600 457 448 9 BD-5 69500 451 444 7 BD-6 71600 461455 6 BD-7 69500 475 462 13 BD-8 42500 450 441 9Manufacturing 1 of Organic EL Device

Organic EL devices were manufactured and evaluated as follows.

Example 1-1

A glass substrate (size: 25 mm×75 mm×1.1 mm thick, manufactured byGeomatec Co., Ltd.) having an ITO transparent electrode (anode) wasultrasonic-cleaned in isopropyl alcohol for five minutes, and thenUV/ozone-cleaned for 30 minutes. A film of ITO was set to be 130-nmthick.

After the glass substrate having the transparent electrode line wascleaned, the glass substrate was mounted on a substrate holder of avacuum evaporation apparatus. Initially, a compound HI wasvapor-deposited on a surface of the glass substrate where thetransparent electrode line was provided in a manner to cover thetransparent electrode, thereby forming a 5-nm-thick hole injectinglayer.

Next, the compound HT1 was vapor-deposited on the hole injecting layerto form an 80-nm-thick first hole transporting layer on the HI film.

Next, a compound HT2 was vapor-deposited on the first hole transportinglayer to form a 10-nm-thick second hole transporting layer.

Further, a compound mCP was vapor-deposited on the second holetransporting layer to form a 5-nm-thick third hole transporting layer.

Further, the compound TADF-1 (the first compound), the compound BD-1(the second compound) and a compound DPEPO (the third compound) wereco-deposited to form a 25-nm-thick emitting layer. A concentration ofthe compound TADF-1 was defined as 24 mass %, a concentration of thecompound BD-1 was defined as 1 mass %, and a concentration of thecompound DPEPO was defined as 75 mass % in the emitting layer.

Next, a compound ET-1 was vapor-deposited on the emitting layer to forma 5-nm-thick first electron transporting layer.

A compound ET-2 was then vapor-deposited on the first electrontransporting layer to form a 20-nm-thick second electron transportinglayer.

Next, lithium fluoride (LiF) was vapor-deposited on the second electrontransporting layer to form a 1-nm-thick electron injecting electrode(cathode).

A metal aluminum (Al) was then vapor-deposited on the electron injectingelectrode to form an 80-nm-thick metal Al cathode.

A device arrangement of the organic EL device of Example 1-1 is roughlyshown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/DPEPO:TADF-1:BD-1(25,75%:24%:1%)/ET-1(5)/ET-2 (20)/LiF(1)/Al(80)

Numerals in parentheses represent a film thickness (unit: nm). Thenumerals represented by percentage in the same parentheses indicate aratio (mass %) of the first compound, the second compound and the thirdcompound in the emitting layer.

Example 1-2

An organic EL device of Example 1-2 was prepared in the same manner asthe organic EL device of Example 1-1 except that a compound BD-2 wasused in place of the compound BD-1 in the emitting layer of Example 1-1.

A device arrangement of the organic EL device of Example 1-2 is roughlyshown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/DPEPO:TADF-1:BD-2(25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Example 1-3

An organic EL device of Example 1-3 was prepared in the same manner asthe organic EL device of Example 1-1 except that a compound BD-3 wasused in place of the compound BD-1 in the emitting layer of Example 1-1.

A device arrangement of the organic EL device of Example 1-3 is roughlyshown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/DPEPO:TADF-1:BD-3(25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Example 1-4

An organic EL device of Example 1-4 was prepared in the same manner asthe organic EL device of Example 1-1 except that a compound BD-4 wasused in place of the compound BD-1 in the emitting layer of Example 1-1.

A device arrangement of the organic EL device of Example 1-4 is roughlyshown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/DPEPO:TADF-1:BD-4(25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Example 1-5

An organic EL device of Example 1-5 was prepared in the same manner asthe organic EL device of Example 1-1 except that a compound BD-6 wasused in place of the compound BD-1 in the emitting layer of Example 1-1.

A device arrangement of the organic EL device of Example 1-5 is roughlyshown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/DPEPO:TADF-1:BD-6(25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Comparative 1-1

An organic EL device of Comparative 1-1 was prepared in the same manneras the organic EL device of Example 1-1 except that a compound TBPe wasused in place of the compound BD-1 in the emitting layer of Example 1-1.

A device arrangement of the organic EL device of Comparative 1-1 isroughly shown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/DPEPO:TADF-1:TBPe(25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Comparative 1-2

An organic EL device of Comparative 1-2 was prepared in the same manneras the organic EL device of Example 1-1 except that a compound ref-1 wasused in place of the compound BD-1 in the emitting layer of Example 1-1.A device arrangement of the organic EL device of Comparative 1-2 isroughly shown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/DPEPO:TADF-1:ref-1(25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Comparative 1-3

An organic EL device of Comparative 1-3 was prepared in the same manneras the organic EL device of Example 1-1 except that a compound ref-2 wasused in place of the compound BD-1 in the emitting layer of Example 1-1.

A device arrangement of the organic EL device of Comparative 1-3 isroughly shown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/DPEPO:TADF-1:ref-2(25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Evaluation 1 of Organic EL Devices

The prepared organic EL devices of Examples 1-1 to 1-5 and Comparatives1-1 to 1-3 were evaluated as follows. The evaluation results are shownin Table 3.

External Quantum Efficiency EQE and Main Peak Wavelength λ_(p)

Voltage was applied on each of the organic EL devices such that thecurrent density was 0.1 mA/cm², where spectral radiance spectrum wasmeasured by a spectroradiometer (CS-1000 manufactured by Konica Minolta,Inc.).

The external quantum efficiency EQE (unit: %) was calculated based onthe obtained spectral-radiance spectra, assuming that the spectra wereprovided under a Lambertian radiation.

The main peak wavelength λ_(p) (unit: nm) was calculated based on theobtained spectral-radiance spectra.

TABLE 3 Second Compound EQE λp Compound Name [%] [nm] Example 1-1 BD-112.9 454 Example 1-2 BD-2 11.6 474 Example 1-3 BD-3 11.1 472 Example 1-4BD-4 13.7 463 Example 1-5 BD-6 12.2 468 Comparative 1-1 TBPe 8.7 464Comparative 1-2 ref-1 9.5 446 Comparative 1-3 ref-2 9.5 446

The organic EL devices of Examples 1-1 to 1-5, in each of which theemitting layer contained the delayed fluorescent first compound and thesecond compound represented by the formula (2), emitted light in a bluewavelength region at a higher efficiency than the organic EL devices ofComparatives 1-1 to 1-3.

Manufacturing 2 of Organic EL Device

Organic EL devices were manufactured and evaluated as follows.

Example 2-1

A glass substrate (size: 25 mm×75 mm×1.1 mm thick, manufactured byGeomatec Co., Ltd.) having an ITO transparent electrode (anode) wasultrasonic-cleaned in isopropyl alcohol for five minutes, and thenUV/ozone-cleaned for 30 minutes. A film of ITO was set to be 130-nmthick.

After the glass substrate having the transparent electrode line wascleaned, the glass substrate was mounted on a substrate holder of avacuum evaporation apparatus. Initially, the compound HI wasvapor-deposited on a surface of the glass substrate where thetransparent electrode line was provided in a manner to cover thetransparent electrode, thereby forming a 5-nm-thick hole injectinglayer.

Next, the compound HT1 was vapor-deposited on the hole injecting layerto form an 80-nm-thick first hole transporting layer on the HI film.

Next, the compound HT2 was vapor-deposited on the first holetransporting layer to form a 10-nm-thick second hole transporting layer.

Further, the compound mCP was vapor-deposited on the second holetransporting layer to form a 5-nm-thick third hole transporting layer.

Further, the compound TADF-2 (the first compound), the compound BD-2(the second compound) and a compound A-1 (the third compound) wereco-deposited on the third hole transporting layer to form a 25-nm-thickemitting layer. A concentration of the compound TADF-2 was defined as 24mass %, a concentration of the compound BD-2 was defined as 1 mass %,and a concentration of the compound A-1 was defined 75 mass % in theemitting layer.

Next, the compound ET-1 was vapor-deposited on the emitting layer toform a 5-nm-thick first electron transporting layer.

The compound ET-2 was then vapor-deposited on the first electrontransporting layer to form a 20-nm-thick second electron transportinglayer.

Next, lithium fluoride (LiF) was vapor-deposited on the second electrontransporting layer to form a 1-nm-thick electron injecting electrode(cathode).

A metal aluminum (Al) was then vapor-deposited on the electron injectingelectrode to form an 80-nm-thick metal Al cathode.

A device arrangement of the organic EL device of Example 2-1 is roughlyshown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/A-1:TADF-2:BD-2 (25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Numerals in parentheses represent a film thickness (unit: nm). Thenumerals represented by percentage in the same parentheses indicate aratio (mass %) of the first compound, the second compound and the thirdcompound in the emitting layer.

Example 2-2

An organic EL device of Example 2-2 was prepared in the same manner asthe organic EL device of Example 2-1 except that the compound BD-3 wasused in place of the compound BD-2 in the emitting layer of Example 2-1.

A device arrangement of the organic EL device of Example 2-2 is roughlyshown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/A-1:TADF-2:BD-3 (25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Example 2-3

An organic EL device of Example 2-3 was prepared in the same manner asthe organic EL device of Example 2-1 except that the compound BD-4 wasused in place of the compound BD-2 in the emitting layer of Example 2-1.

A device arrangement of the organic EL device of Example 2-3 is roughlyshown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/A-1:TADF-2:BD-4 (25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Example 2-4

An organic EL device of Example 2-4 was prepared in the same manner asthe organic EL device of Example 2-1 except that the compound BD-6 wasused in place of the compound BD-2 in the emitting layer of Example 2-1.

A device arrangement of the organic EL device of Example 2-4 is roughlyshown as follows.

ITO(130)/HI(5)/HT1(80)/HT2(10)/mCP(5)/A-1:TADF-2:BD-6 (25,75%:24%:1%)/ET-1(5)/ET-2(20)/LiF(1)/Al(80)

Evaluation 2 of Organic EL Devices

The prepared organic EL devices of Examples 2-1 to 2-4 were evaluated inthe same manner as the organic EL device of Example 1-1. The evaluationresults are shown in Table 4.

TABLE 4 Second Compound Compound EQE λp Name [%] [nm] Example 2-1 BD-215.5 470 Example 2-2 BD-3 15.2 470 Example 2-3 BD-4 16.4 462 Example 2-4BD-6 12.2 468

The organic EL devices of Examples 2-1 to 2-4, in each of which theemitting layer contained the delayed fluorescent first compound and thesecond compound represented by the formula (2), emitted light in a bluewavelength region at a high efficiency in the same manner as in theorganic EL devices of Examples 1-1 to 1-5.

Manufacturing 3 of Organic EL Device

Organic EL devices were manufactured and evaluated as follows.

Example 3-1

A glass substrate (size: 25 mm×75 mm×1.1 mm thick, manufactured byGeomatec Co., Ltd.) having an ITO transparent electrode (anode) wasultrasonic-cleaned in isopropyl alcohol for five minutes, and thenUV/ozone-cleaned for 30 minutes. A film of ITO was set to be 130-nmthick.

After the glass substrate having the transparent electrode line wascleaned, the glass substrate was mounted on a substrate holder of avacuum evaporation apparatus. Initially, a compound HI2 wasvapor-deposited on a surface of the glass substrate where thetransparent electrode line was provided in a manner to cover thetransparent electrode, thereby forming a 5-nm-thick hole injectinglayer.

Next, a compound HT3 was vapor-deposited on the hole injecting layer toform an 80-nm-thick first hole transporting layer on the HI2 film.

Next, a compound HT4 was vapor-deposited on the first hole transportinglayer to form a 10-nm-thick second hole transporting layer.

Further, on the second hole transporting layer, a compound BH and thecompound BD-4 (dopant material) obtained in Synthesis Example 4 wereco-deposited to form a 25-nm-thick emitting layer. A concentration ofthe compound BD-4 (dopant material) in the emitting layer was set at 1mass % and a concentration of the compound BH in the emitting layer wasset at 99 mass %.

Next, a compound ET-3 was vapor-deposited on the emitting layer to forma 10-nm-thick first electron transporting layer.

The compound ET-2 was then vapor-deposited on the first electrontransporting layer to form a 15-nm-thick second electron transportinglayer.

Next, lithium fluoride (LiF) was vapor-deposited on the second electrontransporting layer to form a 1-nm-thick electron injecting electrode(cathode).

A metal aluminum (Al) was then vapor-deposited on the electron injectingelectrode to form an 80-nm-thick metal Al cathode.

A device arrangement of the organic EL device of Example 3-1 is roughlyshown as follows.

ITO(130)/HI2(5)/HT3(80)/HT4(10)/BH:BD-4 (25,99%:1%)/ET-3(10)/ET-2(15)/LiF(1)/Al(80)

Numerals in parentheses represent a film thickness (unit: nm). Thenumerals in the form of percentage in parentheses indicate ratios (mass%) of the compounds BH and BD-4 in the emitting layer.

Comparative 3-1

The organic EL device of Comparative 3-1 was prepared in the same manneras the organic EL device of Example 3-1 except that the compound TBPewas used in place of the compound BD-4 in the emitting layer of Example3-1. A device arrangement of the organic EL device of Comparative 3-1 isroughly shown as follows.

ITO(130)/HI2(5)/HT3(80)/HT4(10)/BH:TBPe (25,99%:1%)/ET-3(10)/ET-2(15)/LiF(1)/Al(80)

Evaluation 3 of Organic EL Devices

The prepared organic EL devices of Example 3-1 and Comparative 3-1 wereevaluated in the same manner as the organic EL device of Example 1-1.The evaluation results are shown in Table 5.

TABLE 5 Second Compound Compound EQE λp Name [%] [nm] Example 3-1 BD-46.9 463 Comparative 3-1 TBPe 5.4 463

The organic EL device of Example 3-1, in which the emitting layercontained the compound BH represented by the formula (15) and thecompound BD-4 represented by the formula (2), emitted light in a bluewavelength region at a higher efficiency than the organic EL device ofComparative 3-1.

The invention claimed is:
 1. A compound represented by a formula (2)below,

where: X₁ to X₅, X₇ to X₁₃, and X₁₆ each independently represent CR_(x)or a carbon atom to be bonded to a structure represented by a formula(2a) or (2b) below; X₆, X₁₄, and X₁₅ each independently representCR_(x); R_(x) each independently represents a hydrogen atom or asubstituent; R_(x) as the substituent is each independently selectedfrom the group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to 30 carbon atoms, a substituted or unsubstituted aryloxy group having6 to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom; a plurality of R_(x)are mutually the same or different; when a plurality of ones of X₁ toX₁₆ are CR_(x) and R_(x) is a substituent, a plurality of R_(x) as thesubstituents are not bonded to each other; and at least one pair of apair of X₁ and X₂, a pair of X₂ and X₃, a pair of X₃ and X₄, a pair ofX₄ and X₅, a pair of X₇ and X₈, a pair of X₈ and X₉, a pair of X₁₀ andX₁₁, a pair of X₁₁ and X₁₂, a pair of X₁₂ and X₁₃, and a pair of X₁₆ andX₁ are carbon atoms to be bonded to the structure represented by theformula (2a) or (2b) below,

in the formula (2a): 2 represent bonding positions to carbon atoms atone pair of the pair of X₁ and X₂, the pair of X₃ and X₄, the pair of X₄and X₅, the pair of X₇ and X₈, the pair of X₈ and X₉, the pair of X₁₀and X₁₁, the pair of X₁₁ and X₁₂, the pair of X₁₂ and X₁₃, and the pairof X₁₆ and X₁ in the formula (2); R₁₁₁ to R₁₁₄ each independentlyrepresent a hydrogen atom or a substituent; R₁₁₁ to R₁₁₄ as thesubstituents are each independently selected from the group consistingof a substituted or unsubstituted alkyl group having 1 to 30 carbonatoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbonatoms, a substituted or unsubstituted alkylthio group having 1 to 30carbon atoms, a substituted or unsubstituted amino group, a substitutedor unsubstituted aryl group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted heteroaryl group having 5 to 30 ring atoms,a substituted or unsubstituted alkenyl group having 2 to 30 carbonatoms, a substituted or unsubstituted aryloxy group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted arylthio group having 6 to30 ring carbon atoms, a substituted or unsubstituted phosphanyl group, asubstituted or unsubstituted phosphoryl group, a substituted orunsubstituted silyl group, a substituted or unsubstituted arylcarbonylgroup having 6 to 30 ring carbon atoms, a cyano group, a nitro group, acarboxy group, and a halogen atom; and at least one pair of a pair ofR₁₁₁ and R₁₁₂, a pair of R₁₁₂ and R₁₁₃, and a pair of R₁₁₃ and R₁₁₄ aresubstituents, and the substituents are bonded to each other to form aring, in the formula (2b): *2 represent bonding positions to carbonatoms at one pair of the pair of X₁ and X₂, the pair of X₂ and X₃, thepair of X₃ and X₄, the pair of X₄ and X₅, the pair of X₇ and X₈, thepair of X₈ and X₉, the pair of X₁₀ and X₁₁, the pair of X₁₁ and X₁₂, thepair of X₁₂ and X₁₃, and the pair of X₁₆ and X₁ in the formula (2); R₁₁₅and R₁₁₆ each independently represent a hydrogen atom or a substituent;R₁₁₅ and R₁₁₆ as the substituents are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to 30 carbon atoms, a substituted or unsubstituted aryloxy group having6 to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom; R₁₁₅ and R₁₁₆ as thesubstituents are bonded to each other to further form a ring, or are notbonded to each other; X is selected from the group consisting of anoxygen atom, a sulfur atom, CR₁₁₇R₁₁₈, SiR₁₁₉R₁₂₀ and NR₁₂₁; R₁₁₇ toR₁₂₁ each independently represent a hydrogen atom or a substituent; R₁₁₇to R₁₂₁ as the substituents are each independently selected from thegroup consisting of a substituted or unsubstituted alkyl group having 1to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1to 30 carbon atoms, a substituted or unsubstituted alkylthio grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted amino group,a substituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, a substituted or unsubstituted alkenyl group having 2 to 30carbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom; R₁₁₇ and R₁₁₈ as thesubstituents are bonded to each other to further form a ring, or are notbonded to each other; and R₁₁₉ and R₁₂₀ as the substituents are bondedto each other to further form a ring, or are not bonded to each other.2. The compound according to claim 1, wherein at least one pair of thepair of X₁ and X₂ and the pair of X₃ and X₄ in the formula (2) arecarbon atoms to be bonded to the structure represented by the formula(2a).
 3. The compound according to claim 1, wherein the structurerepresented by the formula (2a) is a structure represented by a formula(2a-1),

where: *2 represents the same as *2 in the formula (2a); R₁₁₁, R₁₁₂ andR₁₂₂ to R₁₂₅ each independently represent a hydrogen atom or asubstituent; R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ as the substituents are eachindependently selected from the group consisting of a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted orunsubstituted alkylthio group having 1 to 30 carbon atoms, a substitutedor unsubstituted amino group, a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, a substituted orunsubstituted alkenyl group having 2 to 30 carbon atoms, a substitutedor unsubstituted aryloxy group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted arylthio group having 6 to 30 ring carbonatoms, a substituted or unsubstituted phosphanyl group, a substituted orunsubstituted phosphoryl group, a substituted or unsubstituted silylgroup, a substituted or unsubstituted arylcarbonyl group having 6 to 30ring carbon atoms, a cyano group, a nitro group, a carboxy group, and ahalogen atom; and adjacent ones of R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ as thesubstituents are bonded to each other to further form a ring, or are notbonded to each other.
 4. The compound according to claim 3, wherein thecompound represented by the formula (2) is represented by a formula (21A) below,

where: X₃ to X₁₆ and R_(x) respectively represent the same as X₃ to X₁₆and R_(x) in the formula (2), and R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅respectively represent the same as R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ in theformula (2a-1).
 5. The compound according to claim 3, wherein thecompound represented by the formula (2) is represented by a formula(21B) below,

where: X_(b) X₂, X₅ to X₁₆ and R_(x) respectively represent the same asX₁, X₂, X₅ to X₁₆ and R_(x) in the formula (2), and R₁₁₁, R₁₁₂ and R₁₂₂to R₁₂₅ respectively represent the same as R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅in the formula (2a-1).
 6. The compound according to claim 1, wherein atleast one pair of the pair of X₁ and X₂, the pair of X₂ and X₃ and thepair of X₃ and X₄ in the formula (2) are carbon atoms to be bonded tothe structure represented by the formula (2b).
 7. The compound accordingto claim 6, wherein the compound represented by the formula (2) isrepresented by a formula (25 A) below,

where: X₃ to X₁₆ and R_(x) respectively represent the same as X₃ to X₁₆and R_(x) in the formula (2); X represents the same as X in the formula(2b); R₁₂₆ to R₁₂₉ each independently represent a hydrogen atom or asubstituent; R₁₂₆ to R₁₂₉ as the substituents are each independentlyselected from the group consisting of a substituted or unsubstitutedalkyl group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkylthio group having 1 to 30 carbon atoms, a substituted orunsubstituted amino group, a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, a substituted orunsubstituted alkenyl group having 2 to 30 carbon atoms, a substitutedor unsubstituted aryloxy group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted arylthio group having 6 to 30 ring carbonatoms, a substituted or unsubstituted phosphanyl group, a substituted orunsubstituted phosphoryl group, a substituted or unsubstituted silylgroup, a substituted or unsubstituted arylcarbonyl group having 6 to 30ring carbon atoms, a cyano group, a nitro group, a carboxy group, and ahalogen atom; and adjacent ones of R₁₂₆ to R₁₂₉ as the substituents arebonded to each other to further form a ring, or are not bonded to eachother.
 8. The compound according to claim 6, wherein the compoundrepresented by the formula (2) is represented by a formula (25B) below,

where: X₁, X₂, X₅ to X₁₆ and R_(x) respectively represent the same asX₁, X₂, X₅ to X₁₆ and R_(x) in the formula (2); X represents the same asX in the formula (2b); R₁₂₆ to R₁₂₉ each independently represent ahydrogen atom or a substituent; R₁₂₆ to R₁₂₉ as the substituents areeach independently selected from the group consisting of a substitutedor unsubstituted alkyl group having 1 to 30 carbon atoms, a substitutedor unsubstituted alkoxy group having 1 to 30 carbon atoms, a substitutedor unsubstituted alkylthio group having 1 to 30 carbon atoms, asubstituted or unsubstituted amino group, a substituted or unsubstitutedaryl group having 6 to 30 ring carbon atoms, a substituted orunsubstituted heteroaryl group having 5 to 30 ring atoms, a substitutedor unsubstituted alkenyl group having 2 to 30 carbon atoms, asubstituted or unsubstituted aryloxy group having 6 to 30 ring carbonatoms, a substituted or unsubstituted arylthio group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted phosphanyl group, asubstituted or unsubstituted phosphoryl group, a substituted orunsubstituted silyl group, a substituted or unsubstituted arylcarbonylgroup having 6 to 30 ring carbon atoms, a cyano group, a nitro group, acarboxy group, and a halogen atom; and adjacent ones of R₁₂₆ to R₁₂₉ asthe substituents are bonded to each other to further form a ring, or arenot bonded to each other.
 9. The compound according to claim 6, whereinthe compound represented by the formula (2) is represented by a formula(26A) below,

where: X₃ to X₁₆ and R_(x) respectively represent the same as X₃ to X₁₆and R_(x) in the formula (2); X represents the same as X of the formula(2b); R₁₂₆ to R₁₂₉ each independently represent a hydrogen atom or asubstituent; R₁₂₆ to R₁₂₉ as the substituents are each independentlyselected from the group consisting of a substituted or unsubstitutedalkyl group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkoxy group having 1 to 30 carbon atoms, a substituted or unsubstitutedalkylthio group having 1 to 30 carbon atoms, a substituted orunsubstituted amino group, a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, a substituted orunsubstituted alkenyl group having 2 to 30 carbon atoms, a substitutedor unsubstituted aryloxy group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted arylthio group having 6 to 30 ring carbonatoms, a substituted or unsubstituted phosphanyl group, a substituted orunsubstituted phosphoryl group, a substituted or unsubstituted silylgroup, a substituted or unsubstituted arylcarbonyl group having 6 to 30ring carbon atoms, a cyano group, a nitro group, a carboxy group, and ahalogen atom; and adjacent ones of R₁₂₆ to R₁₂₉ as the substituents arebonded to each other to further form a ring, or are not bonded to eachother.
 10. The compound according to claim 6, wherein the compoundrepresented by the formula (2) is represented by a formula (26B) below,

where: X₁, X₂, X₅ to X₁₆ and R_(x) respectively represent the same asX₁, X₂, X₅ to X₁₆ and R_(x) in the formula (2); X represents the same asX in the formula (2b); R₁₂₆ to R₁₂₉ each independently represent ahydrogen atom or a substituent; R₁₂₆ to R₁₂₉ as the substituents areeach independently selected from the group consisting of a substitutedor unsubstituted alley 1 group having 1 to 30 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, asubstituted or unsubstituted alkylthio group having 1 to 30 carbonatoms, a substituted or unsubstituted amino group, a substituted orunsubstituted aryl group having 6 to 30 ring carbon atoms, a substitutedor unsubstituted heteroaryl group having 5 to 30 ring atoms, asubstituted or unsubstituted alkenyl group having 2 to 30 carbon atoms,a substituted or unsubstituted aryloxy group having 6 to 30 ring carbonatoms, a substituted or unsubstituted arylthio group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted phosphanyl group, asubstituted or unsubstituted phosphoryl group, a substituted orunsubstituted silyl group, a substituted or unsubstituted arylcarbonylgroup having 6 to 30 ring carbon atoms, a cyano group, a nitro group, acarboxy group, and a halogen atom; and adjacent ones of R₁₂₆ to R₁₂₉ asthe substituents are bonded to each other to further form a ring, or arenot bonded to each other.
 11. The compound according to claim 1, whereinin the formula (2): X₆ is CR₆; X₁₅ is CR₁₅; and R₆ and R₁₅ are eachindependently a substituted or unsubstituted aryl group having 6 to 30ring carbon atoms.
 12. The compound according to claim 1, wherein in theformula (2), X₆ is CR₆, X₁₅ is CR₁₅, and R₆ and R₁₅ are eachindependently a substituted or unsubstituted phenyl group.
 13. Thecompound according to claim 1, wherein in the formula (2): X₅ is CR₅; X₆is CR₆; X₇ is CR₇; X₈ is CR₈; X₉ is CR₉: X₁₀ is CR₁₀; Xu is CR₁₁; X₁₂ isCR₁₂; X₁₃ is CR₁₃; X₁₄ is CR₁₄; X₁₅ is CR₁₅; X₁₆ is CR₁₆; R₆, and R₁₅are each independently a substituted or unsubstituted phenyl group; andR₅, R₇ to R₁₄, and R₁₆ are hydrogen atoms.
 14. A composition comprisinga plurality of compounds each represented by a formula (2) below,

where: X₁ to X₅, X₇ to X₁₃, and X₁₆ each independently represent CR_(x)or a carbon atom to be bonded to a structure represented by a formula(2a) or (2b) below; X₆, X₁₄, and X₁₅ each independently representCR_(x); R_(x) each independently represents a hydrogen atom or asubstituent; R_(x) as the substituent is each independently selectedfrom the group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to 30 carbon atoms, a substituted or unsubstituted aryloxy group having6 to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom; and a plurality ofR_(x) are mutually the same or different; when a plurality of ones of X₁to X₁₆ are CR_(x) and R_(x) is a substituent, a plurality of R_(x) asthe substituents are not bonded to each other; and at least one pair ofthe pair of X₁ and X₂, the pair of X₂ and X₃, the pair of X₃ and X₄, thepair of X₄ and X₅, the pair of X₇ and X₈, the pair of X₈ and X₉, thepair of X₁₀ and X₁₁, the pair of X₁₁ and X₁₂, the pair of X₁₂ and X₁₃,and the pair of X₁₆ and X₁ are carbon atoms to be bonded to a structurerepresented by the formula (2a) or (2b) below,

in the formula (2a); *2 represent bonding positions to carbon atoms atone pair of the pair of X₁ and X₂, the pair of X₃ and X₄, the pair of X₄and X₅, the pair of X₇ and X₈, the pair of X₈ and X₉, the pair of X₁₀and X₁₁, the pair of X_(H) and X₁₂, the pair of X₁₂ and X₁₃, and thepair of X₁₆ and X₁ in the formula (2); R₁₁₁ to R₁₁₄ each independentlyrepresent a hydrogen atom or a substituent; R₁₁₁ to R₁₁₄ as thesubstituents are each independently selected from the group consistingof a substituted or unsubstituted alkyl group having 1 to 30 carbonatoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbonatoms, a substituted or unsubstituted alkylthio group having 1 to 30carbon atoms, a substituted or unsubstituted amino group, a substitutedor unsubstituted aryl group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted heteroaryl group having 5 to 30 ring atoms,a substituted or unsubstituted alkenyl group having 2 to 30 carbonatoms, a substituted or unsubstituted aryloxy group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted arylthio group having 6 to30 ring carbon atoms, a substituted or unsubstituted phosphanyl group, asubstituted or unsubstituted phosphoryl group, a substituted orunsubstituted silyl group, a substituted or unsubstituted arylcarbonylgroup having 6 to 30 ring carbon atoms, a cyano group, a nitro group, acarboxy group, and a halogen atom; and at least one pair of a pair ofR₁₁₁ and R₁₁₂, a pair of R₁₁₂ and R₁₁₃, and a pair of R₁₁₃ and R₁₁₄ aresubstituents, and the substituents are bonded to each other to form aring, in the formula (2b): *2 represent bonding positions to carbonatoms at one pair of the pair of X₁ and X₂, the pair of X₂ and X₃, thepair of X₃ and X₄, the pair of X₄ and X₅, the pair of X₇ and X₈, thepair of X₈ and X₉, the pair of X₁₀ and X₁₁, the pair of X₁₁ and X₁₂, thepair of X₁₂ and X₁₃, and the pair of X₁₆ and X₁ in the formula (2); R₁₁₅and R₁₁₆ each independently represent a hydrogen atom or a substituent;R₁₁₅ and R₁₁₆ as the substituent are each independently selected fromthe group consisting of a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted alkylthiogroup having 1 to 30 carbon atoms, a substituted or unsubstituted aminogroup, a substituted or unsubstituted aryl group having 6 to 30 ringcarbon atoms, a substituted or unsubstituted heteroaryl group having 5to 30 ring atoms, a substituted or unsubstituted alkenyl group having 2to 30 carbon atoms, a substituted or unsubstituted aryloxy group having6 to 30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom; and R₁₁₅ and R₁₁₆ asthe substituents are bonded to each other to further form a ring, or arenot bonded to each other; X is selected from the group consisting of anoxygen atom, a sulfur atom, CR₁₁₇R₁₁₈, SiR₁₁₉R₁₂₀ and NR₁₂₁; R₁₁₇ toR₁₂₁ each independently represent a hydrogen atom or a substituent; R₁₁₇to R₁₂₁ as the substituents are each independently selected from thegroup consisting of a substituted or unsubstituted alkyl group having 1to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1to 30 carbon atoms, a substituted or unsubstituted alkylthio grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted amino group,a substituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, a substituted or unsubstituted alkenyl group having 2 to 30carbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom; and R₁₁₇ and R₁₁₈ asthe substituents are bonded to each other to further form a ring, or arenot bonded to each other; and R₁₁₉ and R₁₂₀ as the substituents arebonded to each other to further form a ring, or are not bonded to eachother.
 15. The composition according to claim 14, wherein at least onepair of the pair of X₁ and X₂ and the pair of X₃ and X₄ in the formula(2) are carbon atoms to be bonded to the structure represented by theformula (2a).
 16. The composition according to claim 14, wherein thestructure represented by the formula (2a) is a structure represented bya formula (2a-1),

where: *2 represents the same as *2 in the formula (2a); R₁₁₁, R₁₁₂ andR₁₂₂ to R₁₂₅ each independently represent a hydrogen atom or asubstituent; R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ as the substituents are eachindependently selected from the group consisting of a substituted orunsubstituted alkyl group having 1 to 30 carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted orunsubstituted alkylthio group having 1 to 30 carbon atoms, a substitutedor unsubstituted amino group, a substituted or unsubstituted aryl grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedheteroaryl group having 5 to 30 ring atoms, a substituted orunsubstituted alkenyl group having 2 to 30 carbon atoms, a substitutedor unsubstituted aryloxy group having 6 to 30 ring carbon atoms, asubstituted or unsubstituted arylthio group having 6 to 30 ring carbonatoms, a substituted or unsubstituted phosphanyl group, a substituted orunsubstituted phosphoryl group, a substituted or unsubstituted silylgroup, a substituted or unsubstituted arylcarbonyl group having 6 to 30ring carbon atoms, a cyano group, a nitro group, a carboxy group, and ahalogen atom; and adjacent ones of R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ as thesubstituents are bonded to each other to further form a ring, or are notbonded to each other.
 17. The composition according to claim 16, whereinthe composition comprises a compound represented by a formula (21 A)below and a compound represented by a formula (21B) below as thecompounds each represented by the formula (2):

in the formula (21 A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2); in the formula (21B),X₁, X₂, X₅ to X₁₆ and R_(x) respectively represent the same as X_(b) X₂,X₅ to X₁₆ and R_(x) of the formula (2); and in the formulae (21A) and(21B), R₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ respectively represent the same asR₁₁₁, R₁₁₂ and R₁₂₂ to R₁₂₅ of the formula (2a-1).
 18. The compositionaccording to claim 14, wherein at least one pair of the pair of X₁ andX₂, the pair of X₂ and X₃ and the pair of X₃ and X₄ in the formula (2)are carbon atoms to be bonded to the structure represented by theformula (2b).
 19. The composition according to claim 18, wherein thecomposition comprises a compound represented by a formula (25A) belowand a compound represented by a formula (25B) below as the compoundseach represented by the formula (2),

in the formula (25A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2); in the formula (25B),X₁, X₂, X₅ to X₁₆ and R_(x) respectively represent the same as X₁, X₂,X₅ to X₁₆ and R_(x) of the formula (2); in the formulae (25A) and (25B),X represents the same as X of the formula (2b); R₁₂₆ to R₁₂₉ eachindependently represent a hydrogen atom or a substituent; R₁₂₆ to R₁₂₉as the substituents are each independently selected from the groupconsisting of a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted alkylthio group having 1 to30 carbon atoms, a substituted or unsubstituted amino group, asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, a substituted or unsubstituted alkenyl group having 2 to 30carbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphonyl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom; and adjacent ones ofR₁₂₆ to R₁₂₉ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.
 20. The compositionaccording to claim 18, wherein the composition comprises a compoundrepresented by a formula (26A) below and a compound represented by aformula (26B) below as the compounds each represented by the formula(2),

in the formula (26A), X₃ to X₁₆ and R_(x) respectively represent thesame as X₃ to X₁₆ and R_(x) of the formula (2); in the formula (26B),X₁, X₂, X₅ to X₁₆ and R_(x) respectively represent the same as X₁, X₂,X₅ to X₁₆ and R_(x) of the formula (2); in the formulae (26A) and (26B),X represents the same as X of the formula (2b); R₁₂₆ to R₁₂₉ eachindependently represent a hydrogen atom or a substituent; R₁₂₆ to R₁₂₉as the substituents are each independently selected from the groupconsisting of a substituted or unsubstituted alkyl group having 1 to 30carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30carbon atoms, a substituted or unsubstituted alkylthio group having 1 to30 carbon atoms, a substituted or unsubstituted amino group, asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, a substituted or unsubstituted alkenyl group having 2 to 30carbon atoms, a substituted or unsubstituted aryloxy group having 6 to30 ring carbon atoms, a substituted or unsubstituted arylthio grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstitutedphosphanyl group, a substituted or unsubstituted phosphoryl group, asubstituted or unsubstituted silyl group, a substituted or unsubstitutedarylcarbonyl group having 6 to 30 ring carbon atoms, a cyano group, anitro group, a carboxy group, and a halogen atom; and adjacent ones ofR₁₂₆ to R₁₂₉ as the substituents are bonded to each other to furtherform a ring, or are not bonded to each other.
 21. An organicelectroluminescence device comprising: an anode; an emitting layer; anda cathode, wherein the emitting layer comprises a first compound and asecond compound, and the second compound is the compound according toclaim
 1. 22. The organic electroluminescence device according to claim21, wherein the first compound is a delayed fluorescent compound, and asinglet energy S₁(M1) of the first compound and a singlet energy S₁(M2)of the second compound satisfy a relationship of a numerical formula 1below,S ₁(M1)>S ₁(M2)  (Numerical Formula 1).
 23. The organicelectroluminescence device according to claim 22, wherein the secondcompound has a main peak wavelength of an emission spectrum in a rangefrom 430 nm to 480 nm.
 24. The organic electroluminescence deviceaccording to claim 22, wherein the second compound has a main peakwavelength of an emission spectrum in a range from 445 nm to 480 nm. 25.The organic electroluminescence device according to claim 22, whereinthe first compound is a compound represented by a formula (1) below,

where: A is a group having a partial structure selected from the groupconsisting of partial structures represented by formulae (a-1) to (a-7)below; a plurality of A are mutually the same or different; theplurality of A are mutually bonded to form a saturated or unsaturatedring, or not bonded; B is a group having a partial structure selectedfrom the group consisting of partial structures represented by formulae(b-1) to (b-6) below; a plurality of B are mutually the same ordifferent; the plurality of B are mutually bonded to form a saturated orunsaturated ring, or not bonded; a, b and d are each independently aninteger of 1 to 5; c is an integer of 0 to 5; when c is 0, A is bondedto B by a single bond or a spiro bond; when c is an integer of 1 to 5, Lis a linking group selected from the group consisting of a substitutedor unsubstituted aryl group having 6 to 30 ring carbon atoms, and asubstituted or unsubstituted heteroaryl group having 5 to 30 ring atoms;when c is an integer of 2 to 5, a plurality of L are mutually the sameor different; and the plurality of L are mutually bonded to form asaturated or unsaturated ring, or not bonded,

in the formulae (b-1) to (b-6): R each independently represents ahydrogen atom or a substituent; R as the substituent is eachindependently a group selected from the group consisting of asubstituted or unsubstituted aryl group having 6 to 30 ring carbonatoms, a substituted or unsubstituted heteroaryl group having 5 to 30ring atoms, and a substituted or unsubstituted alkyl group having 1 to30 carbon atoms; a plurality of R are mutually the same or different;and the plurality of R are mutually bonded to form a saturated orunsaturated ring, or not bonded.
 26. The organic electroluminescencedevice according to claim 25, wherein A is a group having the partialstructure selected from the group consisting of the partial structuresrepresented by the respective formulae (a-1), (a-2), (a-3) and (a-5).27. The organic electroluminescence device according to claim 25,wherein B is a group having the partial structure selected from thegroup consisting of the partial structures represented by the respectiveformulae (b-2), (b-3) and (b-4).
 28. The organic electroluminescencedevice according to claim 22, wherein the first compound is a compoundrepresented by a formula (11) below,

where: Az is a cyclic structure selected from the group consisting of asubstituted or unsubstituted pyridine ring, a substituted orunsubstituted pyrimidine ring, a substituted or unsubstituted triazinering, and a substituted or unsubstituted pyrazine ring; c is an integerof 0 to 5; when c is 0, Cz and Az are bonded by a single bond; when c isan integer of 1 to 5, L is a linking group selected from the groupconsisting of a substituted or unsubstituted aryl group having 6 to 30ring carbon atoms, and a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring atoms; when c is an integer of 2 to 5, a pluralityof L are mutually the same or different; the plurality of L are mutuallybonded to form a ring, or not bonded; and Cz is represented by a formula(12) below,

where: Y₂₁ to Y₂₈ are each independently a nitrogen atom or CR_(y);R_(y) each independently represents a hydrogen atom or a substituent;R_(y) as the substituent is each independently a group selected from thegroup consisting of a substituted or unsubstituted aryl group having 6to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl grouphaving 5 to 30 ring atoms, a substituted or unsubstituted alkyl grouphaving 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkylgroup having 1 to 30 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 30 ring carbon atoms, a substituted orunsubstituted aralkyl group having 7 to 30 carbon atoms, a substitutedphosphoryl group, a substituted silyl group, a cyano group, a nitrogroup, and a carboxy group; a plurality of R_(y) are mutually the sameor different; when a plurality of ones of Y₂₁ to Y₂₈ are CR_(y) andR_(y) is a substituent, a plurality of R_(y) as the substituents arebonded to each other to form a ring, or are not bonded; and *1represents a bonding position with a carbon atom in a structure of thelinking group represented by L or a bonding position with a carbon atomof the cyclic structure represented by Az.
 29. The organicelectroluminescence device according to claim 22, wherein the emittinglayer further comprises a third compound, and a singlet energy S₁(M1) ofthe first compound and a singlet energy S₁(M3) of the third compoundsatisfy a relationship of a numerical formula 2 below,S ₁(M3)>S ₁(M1)  (Numerical Formula 2).
 30. The organicelectroluminescence device according to claim 29, wherein a contentratio of the first compound in the emitting layer ranges from 10 mass %to 80 mass %.
 31. The organic electroluminescence device according toclaim 21, wherein the emitting layer comprises a plurality of the secondcompounds.
 32. The organic electroluminescence device according to claim21, further comprising: a hole transporting layer between the anode andthe emitting layer.
 33. The organic electroluminescence device accordingto claim 21, further comprising: an electron transporting laver betweenthe cathode and the emitting layer.
 34. An electronic device comprisingthe organic electroluminescence device according to claim 21.